<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:ad9ef6b9-0756-4735-8c01-2a684ee8e974,g:e6d6b05e-9dc6-4823-bd8b-3ae448139486-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.uniti.com/role/ConsolidatedStatementsofIncomeLoss" xlink:type="simple" xlink:href="unit-20241231.xsd#ConsolidatedStatementsofIncomeLoss"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ConsolidatedStatementsofIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_e12a5241-f6a6-4f9a-a329-c102c3ade14c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_StatementTable_e12a5241-f6a6-4f9a-a329-c102c3ade14c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_5e368f28-771d-4684-82d7-3f629ac376a6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_e12a5241-f6a6-4f9a-a329-c102c3ade14c" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_5e368f28-771d-4684-82d7-3f629ac376a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_5e368f28-771d-4684-82d7-3f629ac376a6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5e368f28-771d-4684-82d7-3f629ac376a6" xlink:to="loc_us-gaap_SegmentDomain_5e368f28-771d-4684-82d7-3f629ac376a6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e296016f-f5e5-402a-a879-e43419c179c5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5e368f28-771d-4684-82d7-3f629ac376a6" xlink:to="loc_us-gaap_SegmentDomain_e296016f-f5e5-402a-a879-e43419c179c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasingSegmentMember_1eb49bee-914a-4aca-a822-57d864efa867" xlink:href="unit-20241231.xsd#unit_LeasingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e296016f-f5e5-402a-a879-e43419c179c5" xlink:to="loc_unit_LeasingSegmentMember_1eb49bee-914a-4aca-a822-57d864efa867" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_33e6cd1e-0ff3-41e3-b187-9d595507b8b1" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_e296016f-f5e5-402a-a879-e43419c179c5" xlink:to="loc_unit_FiberSegmentMember_33e6cd1e-0ff3-41e3-b187-9d595507b8b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_25fcf591-00d9-43be-b804-42ac104c915b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_RevenuesAbstract_25fcf591-00d9-43be-b804-42ac104c915b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_7352ae43-9dde-4d53-9607-3ce43b8b4bac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_25fcf591-00d9-43be-b804-42ac104c915b" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_7352ae43-9dde-4d53-9607-3ce43b8b4bac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f26f1bcf-3560-4331-8ac8-18c769cda038" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_25fcf591-00d9-43be-b804-42ac104c915b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_f26f1bcf-3560-4331-8ac8-18c769cda038" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_ae36d0d4-e69c-4648-9d8e-12fe3f1a1433" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_25fcf591-00d9-43be-b804-42ac104c915b" xlink:to="loc_us-gaap_Revenues_ae36d0d4-e69c-4648-9d8e-12fe3f1a1433" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_b51d5b1b-a548-40ad-9cbc-9043718efd5c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_InterestExpense_b51d5b1b-a548-40ad-9cbc-9043718efd5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_8ef41cb5-2527-4682-bd37-f9c6f9f76fe2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_DepreciationAndAmortization_8ef41cb5-2527-4682-bd37-f9c6f9f76fe2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_1babd5a3-8d76-4978-8c09-1c960f0b0984" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_1babd5a3-8d76-4978-8c09-1c960f0b0984" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_135214d9-3370-4d0a-8c2a-7b84be5529d0" xlink:href="unit-20241231.xsd#unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_135214d9-3370-4d0a-8c2a-7b84be5529d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_53118a19-52a4-4c9c-a9b9-101e65defaed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_53118a19-52a4-4c9c-a9b9-101e65defaed" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TransactionRelatedAndOtherCosts_f9162271-a006-49f5-b782-1c2a09b86260" xlink:href="unit-20241231.xsd#unit_TransactionRelatedAndOtherCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_unit_TransactionRelatedAndOtherCosts_f9162271-a006-49f5-b782-1c2a09b86260" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_d385c928-3cbb-4e6e-8bed-7114027aa257" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnSalesOfInvestmentRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_d385c928-3cbb-4e6e-8bed-7114027aa257" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_bab6380f-060f-46b6-a3ae-1253550808d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_bab6380f-060f-46b6-a3ae-1253550808d1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_c4eb037d-9ad0-47e2-80a6-9371bcbfcf37" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherOperatingIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_c4eb037d-9ad0-47e2-80a6-9371bcbfcf37" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_5647ba74-67bb-4c31-9529-178dbc946659" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_3f034598-e9a9-4454-9d38-98f602cf50ab" xlink:to="loc_us-gaap_CostsAndExpenses_5647ba74-67bb-4c31-9529-178dbc946659" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_335659a9-8acd-4e5e-92a0-462d9943defd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_335659a9-8acd-4e5e-92a0-462d9943defd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_c9fa9a36-deec-4d8e-8b6c-0368bb74e063" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_c9fa9a36-deec-4d8e-8b6c-0368bb74e063" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_94d3a89f-e1dc-42b5-bbf0-39e9c41f2c13" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_94d3a89f-e1dc-42b5-bbf0-39e9c41f2c13" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_c4d2e924-b3e5-4233-860e-cec6fb463029" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_ProfitLoss_c4d2e924-b3e5-4233-860e-cec6fb463029" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_1bad3ce2-4591-4780-9317-cb9a977faff3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_1bad3ce2-4591-4780-9317-cb9a977faff3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_b13f7caa-a86d-446b-9b6e-9556655bfe35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_NetIncomeLoss_b13f7caa-a86d-446b-9b6e-9556655bfe35" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_1ba07d45-2abc-4eed-b552-4921bc503e78" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_1ba07d45-2abc-4eed-b552-4921bc503e78" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityDividendsAdjustment_67f8a03e-36af-41a3-913b-a01a69d6d7b5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TemporaryEquityDividendsAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_TemporaryEquityDividendsAdjustment_67f8a03e-36af-41a3-913b-a01a69d6d7b5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_1adb7f4c-571a-48c3-b528-c78724f8ee6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_1adb7f4c-571a-48c3-b528-c78724f8ee6c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_35f819f3-d32c-4cab-8def-2001ad8cba43" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_EarningsPerShareAbstract_35f819f3-d32c-4cab-8def-2001ad8cba43" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_7a11f050-4ca9-474b-9f89-e82ec7076862" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_35f819f3-d32c-4cab-8def-2001ad8cba43" xlink:to="loc_us-gaap_EarningsPerShareBasic_7a11f050-4ca9-474b-9f89-e82ec7076862" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_7e6452bd-4398-4d80-ab3b-a1f5e38d934f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_35f819f3-d32c-4cab-8def-2001ad8cba43" xlink:to="loc_us-gaap_EarningsPerShareDiluted_7e6452bd-4398-4d80-ab3b-a1f5e38d934f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_6604eb67-2ab1-4327-83af-6f4d9205511a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_9705115c-7a10-4988-9bc4-1480b89426a9" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_6604eb67-2ab1-4327-83af-6f4d9205511a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_9c5052ac-f5f1-4ede-99f8-d49143d63452" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_6604eb67-2ab1-4327-83af-6f4d9205511a" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_9c5052ac-f5f1-4ede-99f8-d49143d63452" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_cfc1d821-9d72-4f24-a6ed-917117b3c5f4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_6604eb67-2ab1-4327-83af-6f4d9205511a" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_cfc1d821-9d72-4f24-a6ed-917117b3c5f4" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ConsolidatedStatementsofShareholdersDeficit" xlink:type="simple" xlink:href="unit-20241231.xsd#ConsolidatedStatementsofShareholdersDeficit"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ConsolidatedStatementsofShareholdersDeficit" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_44576944-0c5d-401f-99e2-cc853b566933" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_b843d71b-10f0-4b70-8edf-adc30f56bf8d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_44576944-0c5d-401f-99e2-cc853b566933" xlink:to="loc_us-gaap_StatementTable_b843d71b-10f0-4b70-8edf-adc30f56bf8d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_e93558d2-a2d9-4e57-9a12-c4e1d9988383" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_b843d71b-10f0-4b70-8edf-adc30f56bf8d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_e93558d2-a2d9-4e57-9a12-c4e1d9988383" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_e93558d2-a2d9-4e57-9a12-c4e1d9988383_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e93558d2-a2d9-4e57-9a12-c4e1d9988383" xlink:to="loc_us-gaap_EquityComponentDomain_e93558d2-a2d9-4e57-9a12-c4e1d9988383_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_e93558d2-a2d9-4e57-9a12-c4e1d9988383" xlink:to="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_8ca5d9a8-6adf-49d4-9ce7-f23fade3edf0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_PreferredStockMember_8ca5d9a8-6adf-49d4-9ce7-f23fade3edf0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_d7547bca-d2cd-4939-b5d6-86db7eff40e1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_CommonStockMember_d7547bca-d2cd-4939-b5d6-86db7eff40e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_2f616b84-8ba1-4fe2-97ff-a4fbad2e78da" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_2f616b84-8ba1-4fe2-97ff-a4fbad2e78da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_cc585452-e7f6-4aed-939d-b2d2dc9f407d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_cc585452-e7f6-4aed-939d-b2d2dc9f407d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_83c6c074-4149-418e-bd2a-765c191777fe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncomeMember_83c6c074-4149-418e-bd2a-765c191777fe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_791000da-ca1e-422c-80b4-b01916afedb0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_us-gaap_NoncontrollingInterestMember_791000da-ca1e-422c-80b4-b01916afedb0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NoncontrollingInterestNonVotingPreferredSharesMember_6df93d6e-dd22-41cd-959a-89bb98dcc6d1" xlink:href="unit-20241231.xsd#unit_NoncontrollingInterestNonVotingPreferredSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_34b93e58-cae8-413d-af18-1777c7aa28dc" xlink:to="loc_unit_NoncontrollingInterestNonVotingPreferredSharesMember_6df93d6e-dd22-41cd-959a-89bb98dcc6d1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_44576944-0c5d-401f-99e2-cc853b566933" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_dc419354-cb9f-409d-88de-21a4381cc6e3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_dc419354-cb9f-409d-88de-21a4381cc6e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_77ee1913-0a5a-401f-8817-b6def7c16108" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_77ee1913-0a5a-401f-8817-b6def7c16108" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_74a95523-8176-4b42-ad49-c5375dd39d93" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_74a95523-8176-4b42-ad49-c5375dd39d93" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_943f1d7f-347a-4412-ab99-001543b72f60" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_ProfitLoss_943f1d7f-347a-4412-ab99-001543b72f60" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e182a226-d7c2-4535-b0d7-36ba5d15cd75" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_e182a226-d7c2-4535-b0d7-36ba5d15cd75" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStock_c7813573-98fb-40df-9cd8-83c43c5a9698" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_DividendsCommonStock_c7813573-98fb-40df-9cd8-83c43c5a9698" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NoncontrollingInterestDecreaseIncreaseFromDistributionsToNoncontrollingInterestHolders_f16f3757-4850-49d7-9338-d87d94cd3efb" xlink:href="unit-20241231.xsd#unit_NoncontrollingInterestDecreaseIncreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_unit_NoncontrollingInterestDecreaseIncreaseFromDistributionsToNoncontrollingInterestHolders_f16f3757-4850-49d7-9338-d87d94cd3efb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_37666fbf-6aad-4ff4-a904-3cce7e349736" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_37666fbf-6aad-4ff4-a904-3cce7e349736" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_49870723-a09f-42db-8dd7-ea72766af53f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_49870723-a09f-42db-8dd7-ea72766af53f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_b1f0a65d-3c77-49df-905e-0276ede7daa2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueConversionOfUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueConversionOfUnits_b1f0a65d-3c77-49df-905e-0276ede7daa2" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedPaymentArrangementDecreaseIncreaseForTaxWithholdingObligation_dfe7d07c-45fa-4f5a-9d65-ead32a569c05" xlink:href="unit-20241231.xsd#unit_ShareBasedPaymentArrangementDecreaseIncreaseForTaxWithholdingObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_unit_ShareBasedPaymentArrangementDecreaseIncreaseForTaxWithholdingObligation_dfe7d07c-45fa-4f5a-9d65-ead32a569c05" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_a1e9d8df-c90f-4404-bf97-47156965afaa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_a1e9d8df-c90f-4404-bf97-47156965afaa" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_28659377-3fd7-43ac-ae06-cfc826ac32c0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_28659377-3fd7-43ac-ae06-cfc826ac32c0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_83eb33e2-4461-4be2-9050-8b20d4d3ed4c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_83eb33e2-4461-4be2-9050-8b20d4d3ed4c" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_86c312b0-2c3b-4b29-aa39-583e0b71c80a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueEmployeeStockPurchasePlan_86c312b0-2c3b-4b29-aa39-583e0b71c80a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustmentsToAdditionalPaidInCapitalPaymentsToSettleCappedCallOption_0d147526-1910-412b-8032-a8be12b9e2de" xlink:href="unit-20241231.xsd#unit_AdjustmentsToAdditionalPaidInCapitalPaymentsToSettleCappedCallOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_unit_AdjustmentsToAdditionalPaidInCapitalPaymentsToSettleCappedCallOption_0d147526-1910-412b-8032-a8be12b9e2de" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustmentsToAdditionalPaidInCapitalPaymentForSettlementOfCommonStockWarrant_122255bf-40c8-4c9f-a858-3534fd8b6534" xlink:href="unit-20241231.xsd#unit_AdjustmentsToAdditionalPaidInCapitalPaymentForSettlementOfCommonStockWarrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_unit_AdjustmentsToAdditionalPaidInCapitalPaymentForSettlementOfCommonStockWarrant_122255bf-40c8-4c9f-a858-3534fd8b6534" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustmentsToAdditionalPaidInCapitalTerminationOfBondHedgeOption_3ef0a48b-2a59-479f-9c0a-6af9f3288ebc" xlink:href="unit-20241231.xsd#unit_AdjustmentsToAdditionalPaidInCapitalTerminationOfBondHedgeOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_225f77db-eedb-4d11-9fbc-9d1fd4c34dde" xlink:to="loc_unit_AdjustmentsToAdditionalPaidInCapitalTerminationOfBondHedgeOption_3ef0a48b-2a59-479f-9c0a-6af9f3288ebc" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_c202f1c8-6d4c-457f-b5ba-5defa0146887" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_67d1a6e9-5cbf-490f-92f0-92f0410f1449" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_2af0d89e-2c8a-43b5-8153-3b4fe20b7376" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/OrganizationandDescriptionofBusinessDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#OrganizationandDescriptionofBusinessDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/OrganizationandDescriptionofBusinessDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:href="unit-20241231.xsd#unit_OrganizationAndDescriptionOfBusinessLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:href="unit-20241231.xsd#unit_OrganizationAndDescriptionOfBusinessTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_3cc8b4f9-8e63-4078-80bc-db030ee78060" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_srt_OwnershipAxis_3cc8b4f9-8e63-4078-80bc-db030ee78060" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_3cc8b4f9-8e63-4078-80bc-db030ee78060_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_3cc8b4f9-8e63-4078-80bc-db030ee78060" xlink:to="loc_srt_OwnershipDomain_3cc8b4f9-8e63-4078-80bc-db030ee78060_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_7e8c527b-0a41-450b-b7a9-3a506423bba7" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_3cc8b4f9-8e63-4078-80bc-db030ee78060" xlink:to="loc_srt_OwnershipDomain_7e8c527b-0a41-450b-b7a9-3a506423bba7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPMember_caaea5af-e4f4-450e-964e-15f0df96c9f2" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_7e8c527b-0a41-450b-b7a9-3a506423bba7" xlink:to="loc_unit_UnitiGroupLPMember_caaea5af-e4f4-450e-964e-15f0df96c9f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_1d39e24a-bb2e-4e3b-a6c7-6206879de43b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_1d39e24a-bb2e-4e3b-a6c7-6206879de43b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1d39e24a-bb2e-4e3b-a6c7-6206879de43b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1d39e24a-bb2e-4e3b-a6c7-6206879de43b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_1d39e24a-bb2e-4e3b-a6c7-6206879de43b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7144cac3-25f9-487d-b642-803eef31aa01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_1d39e24a-bb2e-4e3b-a6c7-6206879de43b" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7144cac3-25f9-487d-b642-803eef31aa01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMergerMember_ad5a2d25-1b4b-464e-99b2-6e64a410df39" xlink:href="unit-20241231.xsd#unit_WindstreamMergerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7144cac3-25f9-487d-b642-803eef31aa01" xlink:to="loc_unit_WindstreamMergerMember_ad5a2d25-1b4b-464e-99b2-6e64a410df39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_0ac72e90-9265-40ff-9d5d-bae4416c24fa" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_dei_LegalEntityAxis_0ac72e90-9265-40ff-9d5d-bae4416c24fa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_0ac72e90-9265-40ff-9d5d-bae4416c24fa_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_0ac72e90-9265-40ff-9d5d-bae4416c24fa" xlink:to="loc_dei_EntityDomain_0ac72e90-9265-40ff-9d5d-bae4416c24fa_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_42a3d032-5c6d-4b85-a359-90bec7afd215" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_0ac72e90-9265-40ff-9d5d-bae4416c24fa" xlink:to="loc_dei_EntityDomain_42a3d032-5c6d-4b85-a359-90bec7afd215" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPMember_614d7188-a892-43b8-b121-ea3b4de300b3" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_42a3d032-5c6d-4b85-a359-90bec7afd215" xlink:to="loc_unit_UnitiGroupLPMember_614d7188-a892-43b8-b121-ea3b4de300b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPStockholdersMember_64ec354d-4eba-40ca-9478-67e4b15e76e8" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPStockholdersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_42a3d032-5c6d-4b85-a359-90bec7afd215" xlink:to="loc_unit_UnitiGroupLPStockholdersMember_64ec354d-4eba-40ca-9478-67e4b15e76e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamHoldingsIILLCMember_da67c9c2-0a7a-4f30-af26-ac23300dc08a" xlink:href="unit-20241231.xsd#unit_WindstreamHoldingsIILLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_42a3d032-5c6d-4b85-a359-90bec7afd215" xlink:to="loc_unit_WindstreamHoldingsIILLCMember_da67c9c2-0a7a-4f30-af26-ac23300dc08a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_0976cfca-1d36-4d19-a7a1-5b8575b0b400" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_us-gaap_StatementClassOfStockAxis_0976cfca-1d36-4d19-a7a1-5b8575b0b400" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_0976cfca-1d36-4d19-a7a1-5b8575b0b400_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_0976cfca-1d36-4d19-a7a1-5b8575b0b400" xlink:to="loc_us-gaap_ClassOfStockDomain_0976cfca-1d36-4d19-a7a1-5b8575b0b400_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_607013fb-2a81-449a-913d-81bf8a7baa34" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfStockDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_0976cfca-1d36-4d19-a7a1-5b8575b0b400" xlink:to="loc_us-gaap_ClassOfStockDomain_607013fb-2a81-449a-913d-81bf8a7baa34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_8c8037fd-c818-4b99-986b-86b5a67564e2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockDomain_607013fb-2a81-449a-913d-81bf8a7baa34" xlink:to="loc_us-gaap_CommonStockMember_8c8037fd-c818-4b99-986b-86b5a67564e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PreferredStockDividendsAxis_f7c8f9d0-e98d-448b-adbb-fec4e0834299" xlink:href="unit-20241231.xsd#unit_PreferredStockDividendsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_unit_PreferredStockDividendsAxis_f7c8f9d0-e98d-448b-adbb-fec4e0834299" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PreferredStockDividendsDomain_f7c8f9d0-e98d-448b-adbb-fec4e0834299_default" xlink:href="unit-20241231.xsd#unit_PreferredStockDividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_unit_PreferredStockDividendsAxis_f7c8f9d0-e98d-448b-adbb-fec4e0834299" xlink:to="loc_unit_PreferredStockDividendsDomain_f7c8f9d0-e98d-448b-adbb-fec4e0834299_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PreferredStockDividendsDomain_97a21800-e264-4b47-8f31-8ff76e196b2f" xlink:href="unit-20241231.xsd#unit_PreferredStockDividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_unit_PreferredStockDividendsAxis_f7c8f9d0-e98d-448b-adbb-fec4e0834299" xlink:to="loc_unit_PreferredStockDividendsDomain_97a21800-e264-4b47-8f31-8ff76e196b2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PeriodOneMember_c20ee0d0-3d05-4e2d-b9e2-d85e8e6b6452" xlink:href="unit-20241231.xsd#unit_PeriodOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_PreferredStockDividendsDomain_97a21800-e264-4b47-8f31-8ff76e196b2f" xlink:to="loc_unit_PeriodOneMember_c20ee0d0-3d05-4e2d-b9e2-d85e8e6b6452" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PeriodTwoMember_d9dbeef4-cd5f-4ba7-b1a6-355cb554fa73" xlink:href="unit-20241231.xsd#unit_PeriodTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_PreferredStockDividendsDomain_97a21800-e264-4b47-8f31-8ff76e196b2f" xlink:to="loc_unit_PeriodTwoMember_d9dbeef4-cd5f-4ba7-b1a6-355cb554fa73" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PeriodThreeMember_06f4bfc2-44bf-497c-b12c-8f952ac817f2" xlink:href="unit-20241231.xsd#unit_PeriodThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_PreferredStockDividendsDomain_97a21800-e264-4b47-8f31-8ff76e196b2f" xlink:to="loc_unit_PeriodThreeMember_06f4bfc2-44bf-497c-b12c-8f952ac817f2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessTable_ca29a460-d231-42f0-a2c2-e67ffb2cb169" xlink:to="loc_srt_RangeAxis_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb" xlink:to="loc_srt_RangeMember_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ef6bc876-0bbf-43d8-9bde-ef25650444eb" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_6fb989b9-01d6-40d1-a4f0-a6001c3b23cb" xlink:to="loc_srt_RangeMember_ef6bc876-0bbf-43d8-9bde-ef25650444eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_aa396462-9d51-41cc-a807-ee363d94f2ae" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_ef6bc876-0bbf-43d8-9bde-ef25650444eb" xlink:to="loc_srt_MaximumMember_aa396462-9d51-41cc-a807-ee363d94f2ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_8a438f2f-7376-491f-9773-7bb94cc24fd2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_NumberOfOperatingSegments_8a438f2f-7376-491f-9773-7bb94cc24fd2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_03594633-11d7-4f96-b30d-795b98b7af21" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_03594633-11d7-4f96-b30d-795b98b7af21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_BusinessCombinationNumberOfDirectors_79761bfb-6172-4c8a-b9d6-728194c2771c" xlink:href="unit-20241231.xsd#unit_BusinessCombinationNumberOfDirectors"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_BusinessCombinationNumberOfDirectors_79761bfb-6172-4c8a-b9d6-728194c2771c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_BusinessCombinationNumberOfDirectorsToBeAppointed_8c685412-f87f-4ceb-ad37-202cdc546014" xlink:href="unit-20241231.xsd#unit_BusinessCombinationNumberOfDirectorsToBeAppointed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_BusinessCombinationNumberOfDirectorsToBeAppointed_8c685412-f87f-4ceb-ad37-202cdc546014" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_5fbb0255-e30a-4991-aced-1bc2aa3b4dff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_5fbb0255-e30a-4991-aced-1bc2aa3b4dff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_631c85d7-39b0-471e-9d69-fc58e96882a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_631c85d7-39b0-471e-9d69-fc58e96882a8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage_e16eb9c9-3d63-477f-911f-bf7736ffc10d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_PreferredStockDividendRatePercentage_e16eb9c9-3d63-477f-911f-bf7736ffc10d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PreferredStockDividendRatePercentageTerm_65e65d85-4bb4-4f59-93c9-96dc92c4b09d" xlink:href="unit-20241231.xsd#unit_PreferredStockDividendRatePercentageTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_PreferredStockDividendRatePercentageTerm_65e65d85-4bb4-4f59-93c9-96dc92c4b09d" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PreferredStockDividendRateAnnualIncreasePercentage_b429af78-5329-4736-a140-22342ae8a54a" xlink:href="unit-20241231.xsd#unit_PreferredStockDividendRateAnnualIncreasePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_PreferredStockDividendRateAnnualIncreasePercentage_b429af78-5329-4736-a140-22342ae8a54a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockLiquidationPreferenceValue_9151bbe8-3298-4dc3-b655-dc83ce9877d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockLiquidationPreferenceValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_PreferredStockLiquidationPreferenceValue_9151bbe8-3298-4dc3-b655-dc83ce9877d2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_648a21bc-e9b0-4e01-b92e-5402ec310688" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_648a21bc-e9b0-4e01-b92e-5402ec310688" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ClassOfWarrantOrRightOutstandingStockPercentage_34447991-e321-455a-86f2-8bea4abf7bb8" xlink:href="unit-20241231.xsd#unit_ClassOfWarrantOrRightOutstandingStockPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_OrganizationAndDescriptionOfBusinessLineItems_02e9505c-8345-4998-b67a-ac384667d0f6" xlink:to="loc_unit_ClassOfWarrantOrRightOutstandingStockPercentage_34447991-e321-455a-86f2-8bea4abf7bb8" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SummaryofSignificantAccountingPoliciesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_82500792-cd76-47d4-831d-b0c9b054664e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_82500792-cd76-47d4-831d-b0c9b054664e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_82500792-cd76-47d4-831d-b0c9b054664e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_82500792-cd76-47d4-831d-b0c9b054664e" xlink:to="loc_us-gaap_SegmentDomain_82500792-cd76-47d4-831d-b0c9b054664e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_fe2cac5b-8a2d-45a6-bf3c-7baa24c9edc7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_82500792-cd76-47d4-831d-b0c9b054664e" xlink:to="loc_us-gaap_SegmentDomain_fe2cac5b-8a2d-45a6-bf3c-7baa24c9edc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_122d07ed-0a07-48b6-9e79-4965e158f7af" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_fe2cac5b-8a2d-45a6-bf3c-7baa24c9edc7" xlink:to="loc_unit_FiberSegmentMember_122d07ed-0a07-48b6-9e79-4965e158f7af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_HarmoniTowersLPMember_b547f9ee-0da0-4197-9913-2534ab368b7c" xlink:href="unit-20241231.xsd#unit_HarmoniTowersLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_fe2cac5b-8a2d-45a6-bf3c-7baa24c9edc7" xlink:to="loc_unit_HarmoniTowersLPMember_b547f9ee-0da0-4197-9913-2534ab368b7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_0d716e0f-bcba-49db-afe3-87dfec24e7f4" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_srt_MajorCustomersAxis_0d716e0f-bcba-49db-afe3-87dfec24e7f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_0d716e0f-bcba-49db-afe3-87dfec24e7f4_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_0d716e0f-bcba-49db-afe3-87dfec24e7f4" xlink:to="loc_srt_NameOfMajorCustomerDomain_0d716e0f-bcba-49db-afe3-87dfec24e7f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_45c997b5-a7a1-4376-abe2-b28c17124e1d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_0d716e0f-bcba-49db-afe3-87dfec24e7f4" xlink:to="loc_srt_NameOfMajorCustomerDomain_45c997b5-a7a1-4376-abe2-b28c17124e1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_2b213ec6-7052-4530-a4bb-7e99866811f8" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_45c997b5-a7a1-4376-abe2-b28c17124e1d" xlink:to="loc_unit_WindstreamMember_2b213ec6-7052-4530-a4bb-7e99866811f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_65a01659-c05c-4b21-b964-ab7c4493d92a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_65a01659-c05c-4b21-b964-ab7c4493d92a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_65a01659-c05c-4b21-b964-ab7c4493d92a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_65a01659-c05c-4b21-b964-ab7c4493d92a" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_65a01659-c05c-4b21-b964-ab7c4493d92a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_dde8ab27-297b-4e96-8c78-051ba31b5bb0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_65a01659-c05c-4b21-b964-ab7c4493d92a" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_dde8ab27-297b-4e96-8c78-051ba31b5bb0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_6e1672ab-57ee-4dcc-83cc-8806dca384a0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_dde8ab27-297b-4e96-8c78-051ba31b5bb0" xlink:to="loc_us-gaap_SalesRevenueNetMember_6e1672ab-57ee-4dcc-83cc-8806dca384a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_b8f6ffb5-89c7-4fa1-a468-f76025d7068a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_b8f6ffb5-89c7-4fa1-a468-f76025d7068a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_b8f6ffb5-89c7-4fa1-a468-f76025d7068a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_b8f6ffb5-89c7-4fa1-a468-f76025d7068a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_b8f6ffb5-89c7-4fa1-a468-f76025d7068a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_c0ef7d97-96d3-44e6-aa16-1aa22a8bc998" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_b8f6ffb5-89c7-4fa1-a468-f76025d7068a" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_c0ef7d97-96d3-44e6-aa16-1aa22a8bc998" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_fcce5c2c-8ec7-4976-974a-9dafae7e60cf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_c0ef7d97-96d3-44e6-aa16-1aa22a8bc998" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_fcce5c2c-8ec7-4976-974a-9dafae7e60cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_27688518-a6df-4a79-9847-47a4f5ee425e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_us-gaap_OtherCommitmentsAxis_27688518-a6df-4a79-9847-47a4f5ee425e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_27688518-a6df-4a79-9847-47a4f5ee425e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_27688518-a6df-4a79-9847-47a4f5ee425e" xlink:to="loc_us-gaap_OtherCommitmentsDomain_27688518-a6df-4a79-9847-47a4f5ee425e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_5869db4b-4fcc-460b-95d7-a16e5caca1a3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_27688518-a6df-4a79-9847-47a4f5ee425e" xlink:to="loc_us-gaap_OtherCommitmentsDomain_5869db4b-4fcc-460b-95d7-a16e5caca1a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamCommitmentMember_9f215528-6361-4ee8-b48a-96e042859f6d" xlink:href="unit-20241231.xsd#unit_WindstreamCommitmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_5869db4b-4fcc-460b-95d7-a16e5caca1a3" xlink:to="loc_unit_WindstreamCommitmentMember_9f215528-6361-4ee8-b48a-96e042859f6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamCommitmentGrowthCapitalImprovementsMember_8217dffa-213b-49c2-b65e-965de5d0e3f9" xlink:href="unit-20241231.xsd#unit_WindstreamCommitmentGrowthCapitalImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_5869db4b-4fcc-460b-95d7-a16e5caca1a3" xlink:to="loc_unit_WindstreamCommitmentGrowthCapitalImprovementsMember_8217dffa-213b-49c2-b65e-965de5d0e3f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_97ee1c24-2697-4e0e-90c7-1311e25b11c2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_srt_OwnershipAxis_97ee1c24-2697-4e0e-90c7-1311e25b11c2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_97ee1c24-2697-4e0e-90c7-1311e25b11c2_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_97ee1c24-2697-4e0e-90c7-1311e25b11c2" xlink:to="loc_srt_OwnershipDomain_97ee1c24-2697-4e0e-90c7-1311e25b11c2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_6d8610d1-fffb-4e9e-a139-9e1d769e6927" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_97ee1c24-2697-4e0e-90c7-1311e25b11c2" xlink:to="loc_srt_OwnershipDomain_6d8610d1-fffb-4e9e-a139-9e1d769e6927" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_HarmoniTowersLPMember_88d34c35-4a88-4948-a6b8-141516602bde" xlink:href="unit-20241231.xsd#unit_HarmoniTowersLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_6d8610d1-fffb-4e9e-a139-9e1d769e6927" xlink:to="loc_unit_HarmoniTowersLPMember_88d34c35-4a88-4948-a6b8-141516602bde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_BBFiberHoldingsLLCMember_5dcc47a2-1d8d-4f27-b66c-d9a56ee769b6" xlink:href="unit-20241231.xsd#unit_BBFiberHoldingsLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_6d8610d1-fffb-4e9e-a139-9e1d769e6927" xlink:to="loc_unit_BBFiberHoldingsLLCMember_5dcc47a2-1d8d-4f27-b66c-d9a56ee769b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6fd24337-2541-43d5-9b49-a67641583017" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6fd24337-2541-43d5-9b49-a67641583017" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_6fd24337-2541-43d5-9b49-a67641583017_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6fd24337-2541-43d5-9b49-a67641583017" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_6fd24337-2541-43d5-9b49-a67641583017_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_8e1f2e89-8a3e-4f4b-95b8-6b750c967d6b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_6fd24337-2541-43d5-9b49-a67641583017" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_8e1f2e89-8a3e-4f4b-95b8-6b750c967d6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_HarmoniTowersLPMember_5251968f-d0dd-4b09-904e-62668c0b5911" xlink:href="unit-20241231.xsd#unit_HarmoniTowersLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8e1f2e89-8a3e-4f4b-95b8-6b750c967d6b" xlink:to="loc_unit_HarmoniTowersLPMember_5251968f-d0dd-4b09-904e-62668c0b5911" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_98e30319-d86f-479e-a7d2-049cfdbc2085" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_srt_ConsolidatedEntitiesAxis_98e30319-d86f-479e-a7d2-049cfdbc2085" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_98e30319-d86f-479e-a7d2-049cfdbc2085_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_98e30319-d86f-479e-a7d2-049cfdbc2085" xlink:to="loc_srt_ConsolidatedEntitiesDomain_98e30319-d86f-479e-a7d2-049cfdbc2085_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_5efba238-0914-41be-8e56-187c439cb1f8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_98e30319-d86f-479e-a7d2-049cfdbc2085" xlink:to="loc_srt_ConsolidatedEntitiesDomain_5efba238-0914-41be-8e56-187c439cb1f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_db3c8cf4-93df-46f8-acc9-e63370b91075" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_5efba238-0914-41be-8e56-187c439cb1f8" xlink:to="loc_us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_db3c8cf4-93df-46f8-acc9-e63370b91075" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_0a55afb3-6c15-4931-8471-0af8918cc137" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_srt_CounterpartyNameAxis_0a55afb3-6c15-4931-8471-0af8918cc137" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0a55afb3-6c15-4931-8471-0af8918cc137_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_0a55afb3-6c15-4931-8471-0af8918cc137" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0a55afb3-6c15-4931-8471-0af8918cc137_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1ec794c0-30a5-4d63-80b1-f3c964b9e675" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_0a55afb3-6c15-4931-8471-0af8918cc137" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1ec794c0-30a5-4d63-80b1-f3c964b9e675" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_b7f51bc4-b642-4f34-8c07-27da9da12f2e" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1ec794c0-30a5-4d63-80b1-f3c964b9e675" xlink:to="loc_unit_WindstreamMember_b7f51bc4-b642-4f34-8c07-27da9da12f2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_MacquarieAssetManagementMember_5a95f384-b9cf-41fb-9940-0cbbd186c78b" xlink:href="unit-20241231.xsd#unit_MacquarieAssetManagementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_1ec794c0-30a5-4d63-80b1-f3c964b9e675" xlink:to="loc_unit_MacquarieAssetManagementMember_5a95f384-b9cf-41fb-9940-0cbbd186c78b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_633516f8-d457-471c-953c-bd9347468311" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_d82e0e2e-46c5-4bb2-b50e-5bcc9445a284" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_633516f8-d457-471c-953c-bd9347468311" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_633516f8-d457-471c-953c-bd9347468311_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_633516f8-d457-471c-953c-bd9347468311" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_633516f8-d457-471c-953c-bd9347468311_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d658497b-7568-4ae5-bddc-42bf2b1eca63" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_633516f8-d457-471c-953c-bd9347468311" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d658497b-7568-4ae5-bddc-42bf2b1eca63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMergerMember_6a930372-04cd-46a3-91a2-8d7deafba69f" xlink:href="unit-20241231.xsd#unit_WindstreamMergerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_d658497b-7568-4ae5-bddc-42bf2b1eca63" xlink:to="loc_unit_WindstreamMergerMember_6a930372-04cd-46a3-91a2-8d7deafba69f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_c3a4a7f2-3d3c-4269-b84a-dd91554e175c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_c3a4a7f2-3d3c-4269-b84a-dd91554e175c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_85c932e0-9b05-4c85-b938-fae165879e83" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LitigationSettlementAmountAwardedToOtherParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_85c932e0-9b05-4c85-b938-fae165879e83" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_4fd0cc27-20e2-4b4f-89b7-c2e2c2279f09" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_OtherCommitment_4fd0cc27-20e2-4b4f-89b7-c2e2c2279f09" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireOtherPropertyPlantAndEquipment_8c9a3536-68a0-4e52-a7b4-4fbd42dab676" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsToAcquireOtherPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_PaymentsToAcquireOtherPropertyPlantAndEquipment_8c9a3536-68a0-4e52-a7b4-4fbd42dab676" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_5bb2e64f-35d8-441b-870b-c1dc2e03a8c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_5bb2e64f-35d8-441b-870b-c1dc2e03a8c3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_5698b8fe-5708-4715-b889-be0bf912621f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_5698b8fe-5708-4715-b889-be0bf912621f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_InvestmentReportPeriodLag_5433698e-d96e-48d3-96c2-f632b1f19998" xlink:href="unit-20241231.xsd#unit_InvestmentReportPeriodLag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_unit_InvestmentReportPeriodLag_5433698e-d96e-48d3-96c2-f632b1f19998" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_75b73dec-0dfb-4865-b5b5-beb6f23b9f84" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_75b73dec-0dfb-4865-b5b5-beb6f23b9f84" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_51585032-a809-4928-9ab7-611984a04c7e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_51585032-a809-4928-9ab7-611984a04c7e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_0ab3bca1-e50f-4036-9e7f-3aa2b00bf9e6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_0ab3bca1-e50f-4036-9e7f-3aa2b00bf9e6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainOnSaleOfInvestments_296408b0-9d54-4a01-9850-b94d98a527ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainOnSaleOfInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_GainOnSaleOfInvestments_296408b0-9d54-4a01-9850-b94d98a527ad" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_4006905b-7e81-42ce-8609-8358e905b174" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_4006905b-7e81-42ce-8609-8358e905b174" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_5964909b-ae03-4d13-9b61-2172d60bf679" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_5964909b-ae03-4d13-9b61-2172d60bf679" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_d8e45341-8902-4f7a-bebf-238aee6e2bd2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_d63fe5c5-4716-4fdb-ab63-28d396e4bf3d" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_d8e45341-8902-4f7a-bebf-238aee6e2bd2" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesPropertyPlantandEquipmentandTenantCapitalImprovementsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SummaryofSignificantAccountingPoliciesPropertyPlantandEquipmentandTenantCapitalImprovementsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesPropertyPlantandEquipmentandTenantCapitalImprovementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4270a0c3-31db-4e60-8c1f-db775228928f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4270a0c3-31db-4e60-8c1f-db775228928f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_4270a0c3-31db-4e60-8c1f-db775228928f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4270a0c3-31db-4e60-8c1f-db775228928f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_4270a0c3-31db-4e60-8c1f-db775228928f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a10c78b4-b015-4db2-b43b-6524f05d1189" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4270a0c3-31db-4e60-8c1f-db775228928f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a10c78b4-b015-4db2-b43b-6524f05d1189" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_229a13b3-5dfe-4ab9-bea2-7c59ce0ec1f6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_a10c78b4-b015-4db2-b43b-6524f05d1189" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_229a13b3-5dfe-4ab9-bea2-7c59ce0ec1f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_f688a8fb-181f-42e7-aa94-45d81de81b1e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_f688a8fb-181f-42e7-aa94-45d81de81b1e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_f688a8fb-181f-42e7-aa94-45d81de81b1e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f688a8fb-181f-42e7-aa94-45d81de81b1e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_f688a8fb-181f-42e7-aa94-45d81de81b1e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_b4072026-a982-4945-a1c1-8193dfb59c7c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f688a8fb-181f-42e7-aa94-45d81de81b1e" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_b4072026-a982-4945-a1c1-8193dfb59c7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PropertyPlantAndEquipmentNetMember_7b4ec7aa-eeb3-407d-980f-9763923bb4c7" xlink:href="unit-20241231.xsd#unit_PropertyPlantAndEquipmentNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_b4072026-a982-4945-a1c1-8193dfb59c7c" xlink:to="loc_unit_PropertyPlantAndEquipmentNetMember_7b4ec7aa-eeb3-407d-980f-9763923bb4c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_914b3f9f-f73e-47f0-b413-09eeca1b21fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_914b3f9f-f73e-47f0-b413-09eeca1b21fb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_914b3f9f-f73e-47f0-b413-09eeca1b21fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_914b3f9f-f73e-47f0-b413-09eeca1b21fb" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_914b3f9f-f73e-47f0-b413-09eeca1b21fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_edd8a26e-ed9e-4c70-8c06-b5219d366fd0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_914b3f9f-f73e-47f0-b413-09eeca1b21fb" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_edd8a26e-ed9e-4c70-8c06-b5219d366fd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_MasterLeaseMember_65387cde-610d-424f-b037-52e4f6011877" xlink:href="unit-20241231.xsd#unit_MasterLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_edd8a26e-ed9e-4c70-8c06-b5219d366fd0" xlink:to="loc_unit_MasterLeaseMember_65387cde-610d-424f-b037-52e4f6011877" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ad906a1d-f1ca-408d-a8e7-7099d43bed08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_2c6748ad-ff8a-4a5e-8c79-ced5ac415f08" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ad906a1d-f1ca-408d-a8e7-7099d43bed08" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_ad906a1d-f1ca-408d-a8e7-7099d43bed08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ad906a1d-f1ca-408d-a8e7-7099d43bed08" xlink:to="loc_us-gaap_RelatedPartyDomain_ad906a1d-f1ca-408d-a8e7-7099d43bed08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_11acc8bd-2076-4e75-8192-e57320e05a67" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_ad906a1d-f1ca-408d-a8e7-7099d43bed08" xlink:to="loc_us-gaap_RelatedPartyDomain_11acc8bd-2076-4e75-8192-e57320e05a67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_50a45602-7520-45d1-b7df-1b51f4099d0e" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_11acc8bd-2076-4e75-8192-e57320e05a67" xlink:to="loc_unit_WindstreamMember_50a45602-7520-45d1-b7df-1b51f4099d0e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization_d4b0d607-83c3-4687-b737-9673881609f8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetAccumulatedAmortization_d4b0d607-83c3-4687-b737-9673881609f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_ec125dda-b737-4538-b656-9c9e6eeca3e7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_us-gaap_GainLossOnSaleOfPropertyPlantEquipment_ec125dda-b737-4538-b656-9c9e6eeca3e7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TenantImprovements_97620979-19c1-472a-ab92-dd70d702cbd4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TenantImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_us-gaap_TenantImprovements_97620979-19c1-472a-ab92-dd70d702cbd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingLeasesAmortizedLeaseRevenueRecognized_8f7092e1-2e71-43f8-ab0d-f415d08b6427" xlink:href="unit-20241231.xsd#unit_OperatingLeasesAmortizedLeaseRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_unit_OperatingLeasesAmortizedLeaseRevenueRecognized_8f7092e1-2e71-43f8-ab0d-f415d08b6427" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_7e5d55b5-9c1a-4caf-a613-ae5d4a4bbc12" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_us-gaap_Depreciation_7e5d55b5-9c1a-4caf-a613-ae5d4a4bbc12" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetImpairmentCharges_94f4e440-1b4c-41da-a8e8-6be54762f4f3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_00e78c34-db18-4a26-9b54-ecc71c5ca179" xlink:to="loc_us-gaap_AssetImpairmentCharges_94f4e440-1b4c-41da-a8e8-6be54762f4f3" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesSettlementPayableDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SummaryofSignificantAccountingPoliciesSettlementPayableDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesSettlementPayableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesTable_7f09ff2a-42a9-4f7e-8706-f280a906fec9" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_unit_SummaryOfSignificantAccountingPoliciesTable_7f09ff2a-42a9-4f7e-8706-f280a906fec9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_104f6891-fd79-44f3-8fdf-f0194c82ef9c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_7f09ff2a-42a9-4f7e-8706-f280a906fec9" xlink:to="loc_srt_CounterpartyNameAxis_104f6891-fd79-44f3-8fdf-f0194c82ef9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_104f6891-fd79-44f3-8fdf-f0194c82ef9c_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_104f6891-fd79-44f3-8fdf-f0194c82ef9c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_104f6891-fd79-44f3-8fdf-f0194c82ef9c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_30d5d2bf-cfb8-499a-9baa-89dc8d62eb0c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_104f6891-fd79-44f3-8fdf-f0194c82ef9c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_30d5d2bf-cfb8-499a-9baa-89dc8d62eb0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamCreditorsMember_710de788-23e9-4467-8369-56e3ea7b4154" xlink:href="unit-20241231.xsd#unit_WindstreamCreditorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_30d5d2bf-cfb8-499a-9baa-89dc8d62eb0c" xlink:to="loc_unit_WindstreamCreditorsMember_710de788-23e9-4467-8369-56e3ea7b4154" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_577d077e-69c7-4c10-9046-4fde66bb41ce" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_30d5d2bf-cfb8-499a-9baa-89dc8d62eb0c" xlink:to="loc_unit_WindstreamMember_577d077e-69c7-4c10-9046-4fde66bb41ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_0f71f7a9-3b81-4752-b964-cb63af1630ed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_7f09ff2a-42a9-4f7e-8706-f280a906fec9" xlink:to="loc_us-gaap_TypeOfArrangementAxis_0f71f7a9-3b81-4752-b964-cb63af1630ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0f71f7a9-3b81-4752-b964-cb63af1630ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_0f71f7a9-3b81-4752-b964-cb63af1630ed" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_0f71f7a9-3b81-4752-b964-cb63af1630ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f344a727-5807-43a3-afbe-7bc08a0d84ee" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_0f71f7a9-3b81-4752-b964-cb63af1630ed" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f344a727-5807-43a3-afbe-7bc08a0d84ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_StockPurchaseAgreementsMember_6c32692d-89e4-40b3-9df8-69f5a0880e9b" xlink:href="unit-20241231.xsd#unit_StockPurchaseAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f344a727-5807-43a3-afbe-7bc08a0d84ee" xlink:to="loc_unit_StockPurchaseAgreementsMember_6c32692d-89e4-40b3-9df8-69f5a0880e9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_55266768-18ec-4e4a-94ff-2b7b1f771c2a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_us-gaap_CommonStockSharesIssued_55266768-18ec-4e4a-94ff-2b7b1f771c2a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForLegalSettlements_45bc28ac-bd48-476d-be50-5678aba75a93" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsForLegalSettlements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_us-gaap_PaymentsForLegalSettlements_45bc28ac-bd48-476d-be50-5678aba75a93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_6d37ad07-7c42-46f3-86b6-acbddee12d0f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LitigationSettlementAmountAwardedToOtherParty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_us-gaap_LitigationSettlementAmountAwardedToOtherParty_6d37ad07-7c42-46f3-86b6-acbddee12d0f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LitigationSettlementNumberOfPaymentInstallments_a5826c36-b9c1-4993-ac00-b72876235511" xlink:href="unit-20241231.xsd#unit_LitigationSettlementNumberOfPaymentInstallments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_unit_LitigationSettlementNumberOfPaymentInstallments_a5826c36-b9c1-4993-ac00-b72876235511" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LitigationSettlementPrepaymentDiscountRate_6b22a79b-eea7-44ca-9538-29610792e158" xlink:href="unit-20241231.xsd#unit_LitigationSettlementPrepaymentDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_97135701-aae5-4ccc-9488-b5487d48a65e" xlink:to="loc_unit_LitigationSettlementPrepaymentDiscountRate_6b22a79b-eea7-44ca-9538-29610792e158" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesIncomeTaxesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SummaryofSignificantAccountingPoliciesIncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SummaryofSignificantAccountingPoliciesIncomeTaxesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_e6194300-ce54-4cf4-8d23-c22f1ea46f03" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SummaryOfSignificantAccountingPoliciesTable_e1fae857-de59-45d5-a367-0cb7d183e692" xlink:href="unit-20241231.xsd#unit_SummaryOfSignificantAccountingPoliciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_e6194300-ce54-4cf4-8d23-c22f1ea46f03" xlink:to="loc_unit_SummaryOfSignificantAccountingPoliciesTable_e1fae857-de59-45d5-a367-0cb7d183e692" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_99f15f23-7f70-43c0-8b14-00973a0312c5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_e1fae857-de59-45d5-a367-0cb7d183e692" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_99f15f23-7f70-43c0-8b14-00973a0312c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_99f15f23-7f70-43c0-8b14-00973a0312c5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_99f15f23-7f70-43c0-8b14-00973a0312c5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_99f15f23-7f70-43c0-8b14-00973a0312c5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_ad2243f6-5117-48b8-95ee-41f817e8bee2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_99f15f23-7f70-43c0-8b14-00973a0312c5" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_ad2243f6-5117-48b8-95ee-41f817e8bee2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DeferredIncomeTaxesMember_68c3a6a0-4b44-419f-bd24-b57f82c613cb" xlink:href="unit-20241231.xsd#unit_DeferredIncomeTaxesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_ad2243f6-5117-48b8-95ee-41f817e8bee2" xlink:to="loc_unit_DeferredIncomeTaxesMember_68c3a6a0-4b44-419f-bd24-b57f82c613cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_203c020a-aa0e-4c53-8fe8-96065ab09e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesTable_e1fae857-de59-45d5-a367-0cb7d183e692" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_203c020a-aa0e-4c53-8fe8-96065ab09e8a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_203c020a-aa0e-4c53-8fe8-96065ab09e8a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_203c020a-aa0e-4c53-8fe8-96065ab09e8a" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_203c020a-aa0e-4c53-8fe8-96065ab09e8a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_d6397866-e0fd-4b50-b0c9-a3529230b80f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_203c020a-aa0e-4c53-8fe8-96065ab09e8a" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_d6397866-e0fd-4b50-b0c9-a3529230b80f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_221a765c-311c-49f9-b726-226744895189" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_d6397866-e0fd-4b50-b0c9-a3529230b80f" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_221a765c-311c-49f9-b726-226744895189" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_2aa0a0da-1f78-4d8f-aec2-a27f9b7e37aa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_d6397866-e0fd-4b50-b0c9-a3529230b80f" xlink:to="loc_us-gaap_DomesticCountryMember_2aa0a0da-1f78-4d8f-aec2-a27f9b7e37aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_14724c75-3246-4fcf-95d1-d344bb5f0109" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnrecognizedTaxBenefits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_e6194300-ce54-4cf4-8d23-c22f1ea46f03" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_14724c75-3246-4fcf-95d1-d344bb5f0109" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_GainRecognizedFromSaleOfAssetsAfterSpinoffRecognitionPeriod_fcb36676-0fec-4eeb-91c3-af51cc270e3d" xlink:href="unit-20241231.xsd#unit_GainRecognizedFromSaleOfAssetsAfterSpinoffRecognitionPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_SummaryOfSignificantAccountingPoliciesLineItems_e6194300-ce54-4cf4-8d23-c22f1ea46f03" xlink:to="loc_unit_GainRecognizedFromSaleOfAssetsAfterSpinoffRecognitionPeriod_fcb36676-0fec-4eeb-91c3-af51cc270e3d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/RevenuesScheduleofRevenuesDisaggregatedbyRevenueStreamDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#RevenuesScheduleofRevenuesDisaggregatedbyRevenueStreamDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/RevenuesScheduleofRevenuesDisaggregatedbyRevenueStreamDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_561894c7-4f72-42b2-90d3-abe129dec487" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_4a18af35-6b36-46a0-b576-be4a3a3220e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_561894c7-4f72-42b2-90d3-abe129dec487" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_4a18af35-6b36-46a0-b576-be4a3a3220e5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_d5040af1-4e79-4744-ae3e-ac0180385cd4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_4a18af35-6b36-46a0-b576-be4a3a3220e5" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_d5040af1-4e79-4744-ae3e-ac0180385cd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_d5040af1-4e79-4744-ae3e-ac0180385cd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d5040af1-4e79-4744-ae3e-ac0180385cd4" xlink:to="loc_us-gaap_SegmentDomain_d5040af1-4e79-4744-ae3e-ac0180385cd4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_00d9f46b-6e31-4fbc-b446-53d5f30ba049" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_d5040af1-4e79-4744-ae3e-ac0180385cd4" xlink:to="loc_us-gaap_SegmentDomain_00d9f46b-6e31-4fbc-b446-53d5f30ba049" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_7516dc1f-98d5-45be-a700-7c4ba95d32f9" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_00d9f46b-6e31-4fbc-b446-53d5f30ba049" xlink:to="loc_unit_FiberSegmentMember_7516dc1f-98d5-45be-a700-7c4ba95d32f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasingSegmentMember_d85036b6-c078-4495-a4f4-657e9af98c5b" xlink:href="unit-20241231.xsd#unit_LeasingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_00d9f46b-6e31-4fbc-b446-53d5f30ba049" xlink:to="loc_unit_LeasingSegmentMember_d85036b6-c078-4495-a4f4-657e9af98c5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_ecc7643c-63a8-4acc-8165-437c3efb656d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_4a18af35-6b36-46a0-b576-be4a3a3220e5" xlink:to="loc_srt_ProductOrServiceAxis_ecc7643c-63a8-4acc-8165-437c3efb656d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_ecc7643c-63a8-4acc-8165-437c3efb656d_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_ecc7643c-63a8-4acc-8165-437c3efb656d" xlink:to="loc_srt_ProductsAndServicesDomain_ecc7643c-63a8-4acc-8165-437c3efb656d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_ecc7643c-63a8-4acc-8165-437c3efb656d" xlink:to="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LitBackhaulMember_f0fa9817-bcb0-4cf9-89c0-80a375886693" xlink:href="unit-20241231.xsd#unit_LitBackhaulMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:to="loc_unit_LitBackhaulMember_f0fa9817-bcb0-4cf9-89c0-80a375886693" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_EnterpriseAndWholesaleMember_80d26b34-ba22-4432-b740-097763c35b36" xlink:href="unit-20241231.xsd#unit_EnterpriseAndWholesaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:to="loc_unit_EnterpriseAndWholesaleMember_80d26b34-ba22-4432-b740-097763c35b36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ERateAndGovernmentMember_b2c24ef6-d6ed-4936-bd2c-b42230433d61" xlink:href="unit-20241231.xsd#unit_ERateAndGovernmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:to="loc_unit_ERateAndGovernmentMember_b2c24ef6-d6ed-4936-bd2c-b42230433d61" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OtherRevenueGeneratingActivityMember_6b9f9611-6586-43d4-880e-713124238a20" xlink:href="unit-20241231.xsd#unit_OtherRevenueGeneratingActivityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_63851139-67ad-463e-84f5-de2eadec9dc6" xlink:to="loc_unit_OtherRevenueGeneratingActivityMember_6b9f9611-6586-43d4-880e-713124238a20" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_db6c0a78-f8cd-418b-9b35-bc7141496da4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_561894c7-4f72-42b2-90d3-abe129dec487" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_db6c0a78-f8cd-418b-9b35-bc7141496da4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_3fd8c359-b8ab-4fe0-93cd-9fbabd5bf0ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_561894c7-4f72-42b2-90d3-abe129dec487" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_3fd8c359-b8ab-4fe0-93cd-9fbabd5bf0ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_49fe3f28-1162-48a8-a49a-badd6de9709e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_561894c7-4f72-42b2-90d3-abe129dec487" xlink:to="loc_us-gaap_Revenues_49fe3f28-1162-48a8-a49a-badd6de9709e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/RevenuesAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#RevenuesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/RevenuesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:href="unit-20241231.xsd#unit_RevenueRecognitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:href="unit-20241231.xsd#unit_RevenueRecognitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_60231e12-9ef5-4eb7-9929-d841b4f8da5a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:to="loc_us-gaap_ReceivableTypeDomain_60231e12-9ef5-4eb7-9929-d841b4f8da5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:to="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingLeaseReceivableMember_24d99570-e744-4c7e-98be-86a774bc6c75" xlink:href="unit-20241231.xsd#unit_OperatingLeaseReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:to="loc_unit_OperatingLeaseReceivableMember_24d99570-e744-4c7e-98be-86a774bc6c75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_5ec6a66f-4037-4a25-8843-76172c1d5bd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivablesBillingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_5ec6a66f-4037-4a25-8843-76172c1d5bd4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivablesBillingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BilledRevenuesMember_376ef989-9b89-4888-abb4-faddbab96bcd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BilledRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:to="loc_us-gaap_BilledRevenuesMember_376ef989-9b89-4888-abb4-faddbab96bcd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnbilledRevenuesMember_631010e1-4961-4ce9-8451-343d10c9fcf6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnbilledRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:to="loc_us-gaap_UnbilledRevenuesMember_631010e1-4961-4ce9-8451-343d10c9fcf6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_b7e99fc8-219b-44b6-9d9e-e2335c60ece6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_b7e99fc8-219b-44b6-9d9e-e2335c60ece6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_037778c3-5178-4556-9ba6-3aff55267f2e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_AccountsReceivableNet_037778c3-5178-4556-9ba6-3aff55267f2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_42127952-4f5e-4ea6-a635-f792c7a2cd64" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_42127952-4f5e-4ea6-a635-f792c7a2cd64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_51678bc4-0e99-4f85-a05a-dac4c4af8674" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_51678bc4-0e99-4f85-a05a-dac4c4af8674" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_064a2755-bb6a-4e12-a1ed-52de9a48d34c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_064a2755-bb6a-4e12-a1ed-52de9a48d34c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_fb51ec0d-eaca-4131-94e9-c7ee9e05dc4e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_fb51ec0d-eaca-4131-94e9-c7ee9e05dc4e" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/RevenuesAdditionalInformationDetails_1" xlink:type="simple" xlink:href="unit-20241231.xsd#RevenuesAdditionalInformationDetails_1"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/RevenuesAdditionalInformationDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:href="unit-20241231.xsd#unit_RevenueRecognitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:href="unit-20241231.xsd#unit_RevenueRecognitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_60231e12-9ef5-4eb7-9929-d841b4f8da5a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:to="loc_us-gaap_ReceivableTypeDomain_60231e12-9ef5-4eb7-9929-d841b4f8da5a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_60231e12-9ef5-4eb7-9929-d841b4f8da5a" xlink:to="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingLeaseReceivableMember_24d99570-e744-4c7e-98be-86a774bc6c75" xlink:href="unit-20241231.xsd#unit_OperatingLeaseReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_acf9b895-d64d-469d-8c6e-4c2f17654ced" xlink:to="loc_unit_OperatingLeaseReceivableMember_24d99570-e744-4c7e-98be-86a774bc6c75" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_RevenueRecognitionTable_47187edb-e350-4753-8c08-cbee8a0b642d" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_5ec6a66f-4037-4a25-8843-76172c1d5bd4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivablesBillingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_5ec6a66f-4037-4a25-8843-76172c1d5bd4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReceivablesBillingStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis_5ec6a66f-4037-4a25-8843-76172c1d5bd4" xlink:to="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BilledRevenuesMember_376ef989-9b89-4888-abb4-faddbab96bcd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BilledRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:to="loc_us-gaap_BilledRevenuesMember_376ef989-9b89-4888-abb4-faddbab96bcd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnbilledRevenuesMember_631010e1-4961-4ce9-8451-343d10c9fcf6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnbilledRevenuesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivablesBillingStatusDomain_ff6c4067-348d-454a-a9f3-3fdfbbc9672f" xlink:to="loc_us-gaap_UnbilledRevenuesMember_631010e1-4961-4ce9-8451-343d10c9fcf6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_037778c3-5178-4556-9ba6-3aff55267f2e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_AccountsReceivableNet_037778c3-5178-4556-9ba6-3aff55267f2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_42127952-4f5e-4ea6-a635-f792c7a2cd64" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_42127952-4f5e-4ea6-a635-f792c7a2cd64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_51678bc4-0e99-4f85-a05a-dac4c4af8674" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ContractWithCustomerLiabilityRevenueRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityRevenueRecognized_51678bc4-0e99-4f85-a05a-dac4c4af8674" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_064a2755-bb6a-4e12-a1ed-52de9a48d34c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_064a2755-bb6a-4e12-a1ed-52de9a48d34c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_fb51ec0d-eaca-4131-94e9-c7ee9e05dc4e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_RevenueRecognitionLineItems_616633b6-6f6a-4c46-92c3-1d24f0f77672" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_fb51ec0d-eaca-4131-94e9-c7ee9e05dc4e" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/LeasesAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#LeasesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/LeasesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:href="unit-20241231.xsd#unit_LeasesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:href="unit-20241231.xsd#unit_LeasesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_afc52156-c4aa-4631-b925-e6f3885e1df2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:to="loc_srt_RangeAxis_afc52156-c4aa-4631-b925-e6f3885e1df2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_afc52156-c4aa-4631-b925-e6f3885e1df2_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_afc52156-c4aa-4631-b925-e6f3885e1df2" xlink:to="loc_srt_RangeMember_afc52156-c4aa-4631-b925-e6f3885e1df2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c545ea56-9bff-4e63-be75-a22bba9dece1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_afc52156-c4aa-4631-b925-e6f3885e1df2" xlink:to="loc_srt_RangeMember_c545ea56-9bff-4e63-be75-a22bba9dece1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_08022fd7-83fb-4c52-95b5-20f0155421c1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c545ea56-9bff-4e63-be75-a22bba9dece1" xlink:to="loc_srt_MinimumMember_08022fd7-83fb-4c52-95b5-20f0155421c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_7d322024-2325-43e3-8d7e-6e0fa930e390" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c545ea56-9bff-4e63-be75-a22bba9dece1" xlink:to="loc_srt_MaximumMember_7d322024-2325-43e3-8d7e-6e0fa930e390" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_fde91011-f317-4bd9-8d7a-acd8be90fcd0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:to="loc_srt_MajorCustomersAxis_fde91011-f317-4bd9-8d7a-acd8be90fcd0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_fde91011-f317-4bd9-8d7a-acd8be90fcd0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_fde91011-f317-4bd9-8d7a-acd8be90fcd0" xlink:to="loc_srt_NameOfMajorCustomerDomain_fde91011-f317-4bd9-8d7a-acd8be90fcd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_0bd8e412-a74e-47bf-af02-bcfbfc01045a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_fde91011-f317-4bd9-8d7a-acd8be90fcd0" xlink:to="loc_srt_NameOfMajorCustomerDomain_0bd8e412-a74e-47bf-af02-bcfbfc01045a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_c1911d11-fef7-466a-8a5a-b0b21403d5cb" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_0bd8e412-a74e-47bf-af02-bcfbfc01045a" xlink:to="loc_unit_WindstreamMember_c1911d11-fef7-466a-8a5a-b0b21403d5cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_1019e940-8cad-4036-a0a3-41527c8675cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:to="loc_us-gaap_DebtInstrumentAxis_1019e940-8cad-4036-a0a3-41527c8675cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1019e940-8cad-4036-a0a3-41527c8675cb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_1019e940-8cad-4036-a0a3-41527c8675cb" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1019e940-8cad-4036-a0a3-41527c8675cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0e753bd7-21d3-4f19-ad17-92f00fc485a2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_1019e940-8cad-4036-a0a3-41527c8675cb" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0e753bd7-21d3-4f19-ad17-92f00fc485a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_1b138668-7a16-42d0-b8e5-b78c5079d8de" xlink:href="unit-20241231.xsd#unit_SeniorSecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0e753bd7-21d3-4f19-ad17-92f00fc485a2" xlink:to="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_1b138668-7a16-42d0-b8e5-b78c5079d8de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:to="loc_srt_StatementScenarioAxis_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c" xlink:to="loc_srt_ScenarioUnspecifiedDomain_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_c1f0f948-8f64-4dea-99b0-542aaf17ed7f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_6dc955dc-4ab6-4600-ab6f-670b2a00cc4c" xlink:to="loc_srt_ScenarioUnspecifiedDomain_c1f0f948-8f64-4dea-99b0-542aaf17ed7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProFormaMember_2a73fffc-2ebe-4dc2-9ea1-84c0ca0f92b9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProFormaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_c1f0f948-8f64-4dea-99b0-542aaf17ed7f" xlink:to="loc_srt_ProFormaMember_2a73fffc-2ebe-4dc2-9ea1-84c0ca0f92b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_4ebde22e-e479-4471-86a1-e13d0999d072" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_LeasesTable_2ce42e51-bc1f-460a-a69a-45add33a0e15" xlink:to="loc_us-gaap_TypeOfArrangementAxis_4ebde22e-e479-4471-86a1-e13d0999d072" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_4ebde22e-e479-4471-86a1-e13d0999d072_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TypeOfArrangementAxis_4ebde22e-e479-4471-86a1-e13d0999d072" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_4ebde22e-e479-4471-86a1-e13d0999d072_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_2b0cac5d-a4e2-443a-b4d8-070954c6fcb6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TypeOfArrangementAxis_4ebde22e-e479-4471-86a1-e13d0999d072" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_2b0cac5d-a4e2-443a-b4d8-070954c6fcb6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_EquipmentLoanAgreementMember_bc6e3993-b914-44b3-998d-5456afd414c5" xlink:href="unit-20241231.xsd#unit_EquipmentLoanAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_2b0cac5d-a4e2-443a-b4d8-070954c6fcb6" xlink:to="loc_unit_EquipmentLoanAgreementMember_bc6e3993-b914-44b3-998d-5456afd414c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseTermOfContract_96a1beb4-cb7e-44bd-b993-28335d91ddf5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_LessorOperatingLeaseTermOfContract_96a1beb4-cb7e-44bd-b993-28335d91ddf5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseRenewalTerm_60373628-bd1a-4029-9aee-7d5bfdc23dd2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_LessorOperatingLeaseRenewalTerm_60373628-bd1a-4029-9aee-7d5bfdc23dd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LessorOperatingLeaseTermination_96ba9754-857d-4594-8dc7-6673e8803101" xlink:href="unit-20241231.xsd#unit_LessorOperatingLeaseTermination"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_LessorOperatingLeaseTermination_96ba9754-857d-4594-8dc7-6673e8803101" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_927e55aa-27d5-4ef2-a9ad-630ba95f7db3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_927e55aa-27d5-4ef2-a9ad-630ba95f7db3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_48c78d76-87cf-4db4-969c-ff0a352608ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_48c78d76-87cf-4db4-969c-ff0a352608ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LesseeOperatingLeaseTermination_ed141d70-2401-412e-96f5-c7a19c20b494" xlink:href="unit-20241231.xsd#unit_LesseeOperatingLeaseTermination"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_LesseeOperatingLeaseTermination_ed141d70-2401-412e-96f5-c7a19c20b494" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCommitmentAmount_6c13f5e4-c19b-4855-aa94-59fdd21d045d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShortTermLeaseCommitmentAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_ShortTermLeaseCommitmentAmount_6c13f5e4-c19b-4855-aa94-59fdd21d045d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NumberOfMasterLeases_05bbdf89-dbbe-4e6c-ac56-67c6424fc696" xlink:href="unit-20241231.xsd#unit_NumberOfMasterLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_NumberOfMasterLeases_05bbdf89-dbbe-4e6c-ac56-67c6424fc696" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LessorAnnualPaymentToBeReceived_0b4fd93b-6abc-4e1e-873c-2025e375bc98" xlink:href="unit-20241231.xsd#unit_LessorAnnualPaymentToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_LessorAnnualPaymentToBeReceived_0b4fd93b-6abc-4e1e-873c-2025e375bc98" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_32cf4f2d-61db-4fac-8838-be33a903788e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_32cf4f2d-61db-4fac-8838-be33a903788e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DebtInstrumentCovenantLeverageRatio_3d93576d-5e11-4324-bd71-5854c8b81775" xlink:href="unit-20241231.xsd#unit_DebtInstrumentCovenantLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_DebtInstrumentCovenantLeverageRatio_3d93576d-5e11-4324-bd71-5854c8b81775" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovements_f52fb605-dd22-482b-ae18-c19de88fbfa5" xlink:href="unit-20241231.xsd#unit_NewLeasesAgreementToFundGrowthCapitalImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovements_f52fb605-dd22-482b-ae18-c19de88fbfa5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_GrowthCapitalImprovementsExcludeLimitForMaintenanceOrRepairExpendituresExceptCostsIncurredForFiberReplacementToLeasedProperty_54e96179-3b07-45ad-9410-60fe38501aae" xlink:href="unit-20241231.xsd#unit_GrowthCapitalImprovementsExcludeLimitForMaintenanceOrRepairExpendituresExceptCostsIncurredForFiberReplacementToLeasedProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_GrowthCapitalImprovementsExcludeLimitForMaintenanceOrRepairExpendituresExceptCostsIncurredForFiberReplacementToLeasedProperty_54e96179-3b07-45ad-9410-60fe38501aae" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearOne_eb347da3-1cd7-48c7-ad4d-e0f485875139" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearOne"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearOne_eb347da3-1cd7-48c7-ad4d-e0f485875139" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTwoThroughFive_aa410ab8-a039-489c-85b7-503681c7abb2" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTwoThroughFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTwoThroughFive_aa410ab8-a039-489c-85b7-503681c7abb2" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSix_c190ddab-0df2-4e1e-8e78-119d71346a65" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSix"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSix_c190ddab-0df2-4e1e-8e78-119d71346a65" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSeven_841bbc04-723e-4a47-813a-f9e5caf717e9" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSeven"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearSeven_841bbc04-723e-4a47-813a-f9e5caf717e9" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearEight_e7def949-066a-40d6-8743-c0c9ee7328fa" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearEight"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearEight_e7def949-066a-40d6-8743-c0c9ee7328fa" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearNine_c18b1e18-e0d2-45ec-81fb-8f92fe158069" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearNine"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearNine_c18b1e18-e0d2-45ec-81fb-8f92fe158069" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTen_cde51883-0829-4730-adec-bf0b2df441d0" xlink:href="unit-20241231.xsd#unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTen"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_FutureAnnualCommitmentPaymentsForAgreementsDueYearTen_cde51883-0829-4730-adec-bf0b2df441d0" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CumulativeGrowthCapitalImprovementsAnnualReimbursementCommitmentAmountLimitInSubsequentPeriod_8dee9b14-1430-427f-a949-42629a383a20" xlink:href="unit-20241231.xsd#unit_CumulativeGrowthCapitalImprovementsAnnualReimbursementCommitmentAmountLimitInSubsequentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_CumulativeGrowthCapitalImprovementsAnnualReimbursementCommitmentAmountLimitInSubsequentPeriod_8dee9b14-1430-427f-a949-42629a383a20" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AnnualRentAdjustmentForGrowthCapitalFunding_5fc4819a-078b-4be0-ba24-ec9a6833ba05" xlink:href="unit-20241231.xsd#unit_AnnualRentAdjustmentForGrowthCapitalFunding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_AnnualRentAdjustmentForGrowthCapitalFunding_5fc4819a-078b-4be0-ba24-ec9a6833ba05" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_RateUsedForRentPercentage_2326bff7-5820-4e3e-9fba-e75f2b8607f1" xlink:href="unit-20241231.xsd#unit_RateUsedForRentPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_RateUsedForRentPercentage_2326bff7-5820-4e3e-9fba-e75f2b8607f1" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_MaximumFundingRightsAllocatedPerYearUponTransferOfInterestsUnderNewLease_df241eb0-3cf5-4180-be35-1c0c304986bd" xlink:href="unit-20241231.xsd#unit_MaximumFundingRightsAllocatedPerYearUponTransferOfInterestsUnderNewLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_MaximumFundingRightsAllocatedPerYearUponTransferOfInterestsUnderNewLease_df241eb0-3cf5-4180-be35-1c0c304986bd" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovementsMaximumAnnualAmount_844fa963-c749-4fcf-98a6-0c8bf636dbf1" xlink:href="unit-20241231.xsd#unit_NewLeasesAgreementToFundGrowthCapitalImprovementsMaximumAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovementsMaximumAnnualAmount_844fa963-c749-4fcf-98a6-0c8bf636dbf1" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AccruedInterestRateForBorrowing_42f91633-984c-4269-91df-c131abe34406" xlink:href="unit-20241231.xsd#unit_AccruedInterestRateForBorrowing"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_AccruedInterestRateForBorrowing_42f91633-984c-4269-91df-c131abe34406" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovementsLoanAmount_237e6dd6-3496-4cfb-b803-a2817a1db2b3" xlink:href="unit-20241231.xsd#unit_NewLeasesAgreementToFundGrowthCapitalImprovementsLoanAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovementsLoanAmount_237e6dd6-3496-4cfb-b803-a2817a1db2b3" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ReimbursementToFundGrowthCapitalImprovements_eb1c88b2-c1eb-4dbb-8fbf-22067cb6dd16" xlink:href="unit-20241231.xsd#unit_ReimbursementToFundGrowthCapitalImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_ReimbursementToFundGrowthCapitalImprovements_eb1c88b2-c1eb-4dbb-8fbf-22067cb6dd16" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AmountAllowedForUnderSettlementRepresentedReimbursementOfCapitalImprovements_fd834455-c254-426b-9ac1-e106b69ad5dd" xlink:href="unit-20241231.xsd#unit_AmountAllowedForUnderSettlementRepresentedReimbursementOfCapitalImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_LeasesLineItems_e24e7c95-ca4e-4d89-a2d6-5faa2e26b271" xlink:to="loc_unit_AmountAllowedForUnderSettlementRepresentedReimbursementOfCapitalImprovements_fd834455-c254-426b-9ac1-e106b69ad5dd" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/LeasesScheduleofLeasePaymentstobeReceivedunderNonCancellableOperatingLeasesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#LeasesScheduleofLeasePaymentstobeReceivedunderNonCancellableOperatingLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/LeasesScheduleofLeasePaymentstobeReceivedunderNonCancellableOperatingLeasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_5031504e-e03e-48d2-9ec6-33611b390051" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_5031504e-e03e-48d2-9ec6-33611b390051" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_4754c45d-21a5-4726-b6b4-026e21fb5e5b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_5031504e-e03e-48d2-9ec6-33611b390051" xlink:to="loc_srt_MajorCustomersAxis_4754c45d-21a5-4726-b6b4-026e21fb5e5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_4754c45d-21a5-4726-b6b4-026e21fb5e5b_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_4754c45d-21a5-4726-b6b4-026e21fb5e5b" xlink:to="loc_srt_NameOfMajorCustomerDomain_4754c45d-21a5-4726-b6b4-026e21fb5e5b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_319dd01f-e27e-4c1b-a605-538bacce0160" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_4754c45d-21a5-4726-b6b4-026e21fb5e5b" xlink:to="loc_srt_NameOfMajorCustomerDomain_319dd01f-e27e-4c1b-a605-538bacce0160" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_6073ad01-f708-42a6-8647-70a3c2393a08" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_319dd01f-e27e-4c1b-a605-538bacce0160" xlink:to="loc_unit_WindstreamMember_6073ad01-f708-42a6-8647-70a3c2393a08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_8fdd8341-d55d-49bd-a79e-5db9c09cd396" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_8fdd8341-d55d-49bd-a79e-5db9c09cd396" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bd8268f0-9e1d-4747-9f8e-cd3548ec9f52" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bd8268f0-9e1d-4747-9f8e-cd3548ec9f52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_9544c1b6-e6cc-4bbe-b741-1be6603c71b3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_9544c1b6-e6cc-4bbe-b741-1be6603c71b3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_9bf0267c-e778-4582-8b3f-8038c632e738" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_9bf0267c-e778-4582-8b3f-8038c632e738" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_95c614e9-3384-47c5-bef6-44b0725b3cf2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_95c614e9-3384-47c5-bef6-44b0725b3cf2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_3b2f23a4-2fd5-4ffd-ab11-bb66b15c3fb8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_3b2f23a4-2fd5-4ffd-ab11-bb66b15c3fb8" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_128af0a1-123a-40e8-8683-f5df67bb8b99" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ed076cd4-12df-4e62-a597-3718aaa95bb9" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_128af0a1-123a-40e8-8683-f5df67bb8b99" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_ca14ec06-0159-4fc2-86a8-826266927cac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/LeasesScheduleofUnderlyingAssetsunderOperatingLeasesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#LeasesScheduleofUnderlyingAssetsunderOperatingLeasesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/LeasesScheduleofUnderlyingAssetsunderOperatingLeasesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_791c4795-647d-4dbe-ab96-d736c43ca51e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_791c4795-647d-4dbe-ab96-d736c43ca51e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c1b98567-d6e6-4f54-ac32-1751d821e4d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_791c4795-647d-4dbe-ab96-d736c43ca51e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c1b98567-d6e6-4f54-ac32-1751d821e4d1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c1b98567-d6e6-4f54-ac32-1751d821e4d1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c1b98567-d6e6-4f54-ac32-1751d821e4d1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_c1b98567-d6e6-4f54-ac32-1751d821e4d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_c1b98567-d6e6-4f54-ac32-1751d821e4d1" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_399e8152-00ea-45b4-8dee-1ea9cdfe2096" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_us-gaap_LandMember_399e8152-00ea-45b4-8dee-1ea9cdfe2096" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_22961cdf-fa7f-45ff-b185-ae66a9755df0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_22961cdf-fa7f-45ff-b185-ae66a9755df0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PolesMember_80786740-6329-4613-b9ed-eb911c7e719e" xlink:href="unit-20241231.xsd#unit_PolesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_PolesMember_80786740-6329-4613-b9ed-eb911c7e719e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberMember_56d1f8d9-f28d-4364-a723-cc03fce2ace1" xlink:href="unit-20241231.xsd#unit_FiberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_FiberMember_56d1f8d9-f28d-4364-a723-cc03fce2ace1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_fbe35644-8d4a-416b-893a-eece2654ca27" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_us-gaap_EquipmentMember_fbe35644-8d4a-416b-893a-eece2654ca27" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CopperMember_d5bce217-07c1-462e-88b0-65394a2ed512" xlink:href="unit-20241231.xsd#unit_CopperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_CopperMember_d5bce217-07c1-462e-88b0-65394a2ed512" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConduitMember_a5b691dd-e5fe-4fea-a91b-e2a739b23485" xlink:href="unit-20241231.xsd#unit_ConduitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_ConduitMember_a5b691dd-e5fe-4fea-a91b-e2a739b23485" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TowerAssetsMember_d15148b8-646e-4c51-a1cb-10581eb7e9a5" xlink:href="unit-20241231.xsd#unit_TowerAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_TowerAssetsMember_d15148b8-646e-4c51-a1cb-10581eb7e9a5" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FinanceLeaseAssetsLeasedToOthersMember_a20838cc-47ae-46ab-97b8-963da8e9318b" xlink:href="unit-20241231.xsd#unit_FinanceLeaseAssetsLeasedToOthersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_unit_FinanceLeaseAssetsLeasedToOthersMember_a20838cc-47ae-46ab-97b8-963da8e9318b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_111f7786-d548-4946-99a7-5fb9fb441d4f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_8c00fd15-6eb8-4aae-a353-045db83dc269" xlink:to="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_111f7786-d548-4946-99a7-5fb9fb441d4f" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross_3b8ed470-9e3a-469a-9675-6a26a17d1e70" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_us-gaap_PropertySubjectToOrAvailableForOperatingLeaseGross_3b8ed470-9e3a-469a-9675-6a26a17d1e70" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_86583ed7-dcdc-48c7-aeb8-f0fe4cd51b4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_86583ed7-dcdc-48c7-aeb8-f0fe4cd51b4b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciationAndAmortization_72462a63-be7b-40de-9d22-3704cd081fe3" xlink:href="unit-20241231.xsd#unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseBeforeAccumulatedDepreciationAndAmortization_72462a63-be7b-40de-9d22-3704cd081fe3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAccumulatedDepreciationAndAmortization_822866ca-3ba5-44ba-be5e-f463e6a0613c" xlink:href="unit-20241231.xsd#unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAccumulatedDepreciationAndAmortization_822866ca-3ba5-44ba-be5e-f463e6a0613c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAfterAccumulatedDepreciationAndAmortization_221186c4-2f73-40a3-b847-0e4814c5aed9" xlink:href="unit-20241231.xsd#unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_039c9bae-c6ab-4263-b9c0-bac5a8ddcb42" xlink:to="loc_unit_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetLessorAssetUnderOperatingLeaseAfterAccumulatedDepreciationAndAmortization_221186c4-2f73-40a3-b847-0e4814c5aed9" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/LeasesScheduleofFutureSubleaseRentalsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#LeasesScheduleofFutureSubleaseRentalsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/LeasesScheduleofFutureSubleaseRentalsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_6606479d-c232-4024-a92c-a32776079310" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_6606479d-c232-4024-a92c-a32776079310" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermAxis_895aa959-0dde-49e9-bccc-770862d68d46" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LeaseContractualTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_6606479d-c232-4024-a92c-a32776079310" xlink:to="loc_us-gaap_LeaseContractualTermAxis_895aa959-0dde-49e9-bccc-770862d68d46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_895aa959-0dde-49e9-bccc-770862d68d46_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LeaseContractualTermAxis_895aa959-0dde-49e9-bccc-770862d68d46" xlink:to="loc_us-gaap_LeaseContractualTermDomain_895aa959-0dde-49e9-bccc-770862d68d46_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseContractualTermDomain_e0138173-5137-4eea-a923-005e444f52b8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LeaseContractualTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LeaseContractualTermAxis_895aa959-0dde-49e9-bccc-770862d68d46" xlink:to="loc_us-gaap_LeaseContractualTermDomain_e0138173-5137-4eea-a923-005e444f52b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SubleaseRentalsMember_05034359-b59b-45f6-acda-dd5d5e87c20f" xlink:href="unit-20241231.xsd#unit_SubleaseRentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseContractualTermDomain_e0138173-5137-4eea-a923-005e444f52b8" xlink:to="loc_unit_SubleaseRentalsMember_05034359-b59b-45f6-acda-dd5d5e87c20f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_1eae8de4-4309-4776-a6d1-6eb4c28640b8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_1eae8de4-4309-4776-a6d1-6eb4c28640b8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bc4b4a7c-78c0-40bf-8f90-8eeb7fbb24d0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bc4b4a7c-78c0-40bf-8f90-8eeb7fbb24d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_35bb7006-e6a4-48c8-a417-9364851f7ca6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_35bb7006-e6a4-48c8-a417-9364851f7ca6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_43ccdeae-6749-4cd6-a1c2-bc20331e12fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_43ccdeae-6749-4cd6-a1c2-bc20331e12fb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_c4031a05-a1a6-4da4-a938-ba4ba34065e1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFiveYears_c4031a05-a1a6-4da4-a938-ba4ba34065e1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_d867dd12-881c-4b94-ad8c-3884219272f2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_d867dd12-881c-4b94-ad8c-3884219272f2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_f93139c2-7777-42e1-a1ad-57675288be98" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_0a1d9d74-ca8e-43f1-96aa-1a23f4e6923d" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_f93139c2-7777-42e1-a1ad-57675288be98" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/AssetsandLiabilitiesHeldforSaleAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#AssetsandLiabilitiesHeldforSaleAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/AssetsandLiabilitiesHeldforSaleAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_93aa136d-00b3-4389-9a01-e7ebe354c07c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d970e14a-8aa8-463f-aa00-8544edcbc372" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_93aa136d-00b3-4389-9a01-e7ebe354c07c" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d970e14a-8aa8-463f-aa00-8544edcbc372" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d970e14a-8aa8-463f-aa00-8544edcbc372" xlink:to="loc_srt_CounterpartyNameAxis_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_369aff5d-100d-467a-903f-e6f3c759ccaf" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_45aa6bb1-2c2b-4c6c-b227-f0e68cae3e31" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_369aff5d-100d-467a-903f-e6f3c759ccaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_MacquarieAssetManagementMember_ab217eb8-165e-4d8e-8e41-c96fa20b5c97" xlink:href="unit-20241231.xsd#unit_MacquarieAssetManagementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_369aff5d-100d-467a-903f-e6f3c759ccaf" xlink:to="loc_unit_MacquarieAssetManagementMember_ab217eb8-165e-4d8e-8e41-c96fa20b5c97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_a5a2921f-80bc-4898-92de-affea45526ac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d970e14a-8aa8-463f-aa00-8544edcbc372" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_a5a2921f-80bc-4898-92de-affea45526ac" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_a5a2921f-80bc-4898-92de-affea45526ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_a5a2921f-80bc-4898-92de-affea45526ac" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_a5a2921f-80bc-4898-92de-affea45526ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_5d1bf969-fce6-40da-906a-88cf9701dcbe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_a5a2921f-80bc-4898-92de-affea45526ac" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_5d1bf969-fce6-40da-906a-88cf9701dcbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_cd131843-ed11-4ca4-a7c8-ec060183e051" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_5d1bf969-fce6-40da-906a-88cf9701dcbe" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_cd131843-ed11-4ca4-a7c8-ec060183e051" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_bfd19346-9516-459d-9a5d-997b25a94535" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_d970e14a-8aa8-463f-aa00-8544edcbc372" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_bfd19346-9516-459d-9a5d-997b25a94535" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_bfd19346-9516-459d-9a5d-997b25a94535_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_bfd19346-9516-459d-9a5d-997b25a94535" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_bfd19346-9516-459d-9a5d-997b25a94535_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_9d906800-1452-4484-ac2f-d1bd1f1fc3d8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_bfd19346-9516-459d-9a5d-997b25a94535" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_9d906800-1452-4484-ac2f-d1bd1f1fc3d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CableSouthTransactionMember_4a39861a-51f6-4d79-8666-6d9cb8ec9fc4" xlink:href="unit-20241231.xsd#unit_CableSouthTransactionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_9d906800-1452-4484-ac2f-d1bd1f1fc3d8" xlink:to="loc_unit_CableSouthTransactionMember_4a39861a-51f6-4d79-8666-6d9cb8ec9fc4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_9da7894f-8d28-4027-b68c-8c4ee9562be4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_93aa136d-00b3-4389-9a01-e7ebe354c07c" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_9da7894f-8d28-4027-b68c-8c4ee9562be4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_673bfb7c-a3e0-44b4-a1b1-bd250f785221" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnSalesOfInvestmentRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_93aa136d-00b3-4389-9a01-e7ebe354c07c" xlink:to="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_673bfb7c-a3e0-44b4-a1b1-bd250f785221" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/AssetsandLiabilitiesHeldforSaleScheduleofAssetsandLiabilitiesHeldforSaleDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#AssetsandLiabilitiesHeldforSaleScheduleofAssetsandLiabilitiesHeldforSaleDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/AssetsandLiabilitiesHeldforSaleScheduleofAssetsandLiabilitiesHeldforSaleDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_48d9b445-ce34-40b4-a83a-6eb80143e604" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_48d9b445-ce34-40b4-a83a-6eb80143e604" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_68ae3e93-d5c1-42a3-b66b-748660301ca8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_48d9b445-ce34-40b4-a83a-6eb80143e604" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_68ae3e93-d5c1-42a3-b66b-748660301ca8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_68ae3e93-d5c1-42a3-b66b-748660301ca8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_68ae3e93-d5c1-42a3-b66b-748660301ca8" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_68ae3e93-d5c1-42a3-b66b-748660301ca8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_156ff254-1c94-4819-8b47-ca039ca167d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_68ae3e93-d5c1-42a3-b66b-748660301ca8" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_156ff254-1c94-4819-8b47-ca039ca167d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_17ec4171-fe1e-4209-b18e-f86941410db6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_156ff254-1c94-4819-8b47-ca039ca167d2" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_17ec4171-fe1e-4209-b18e-f86941410db6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0c848765-a4be-4b40-b63b-383ecafd1e5b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_48d9b445-ce34-40b4-a83a-6eb80143e604" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0c848765-a4be-4b40-b63b-383ecafd1e5b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0c848765-a4be-4b40-b63b-383ecafd1e5b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0c848765-a4be-4b40-b63b-383ecafd1e5b" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0c848765-a4be-4b40-b63b-383ecafd1e5b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6c19506e-a0c6-4375-81ba-fbb7ef51c3d2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0c848765-a4be-4b40-b63b-383ecafd1e5b" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6c19506e-a0c6-4375-81ba-fbb7ef51c3d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CableSouthTransactionMember_1739b43b-644f-489b-a79a-2d6ad94846d0" xlink:href="unit-20241231.xsd#unit_CableSouthTransactionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_6c19506e-a0c6-4375-81ba-fbb7ef51c3d2" xlink:to="loc_unit_CableSouthTransactionMember_1739b43b-644f-489b-a79a-2d6ad94846d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_706fd317-7f5b-4423-8b46-bc8f0ea8c74a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipment_706fd317-7f5b-4423-8b46-bc8f0ea8c74a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DisposalGroupIncludingDiscontinuedOperationStraightLineRevenueReceivable_e00eda0f-2e63-4cb8-8a8d-bfa3f7972a59" xlink:href="unit-20241231.xsd#unit_DisposalGroupIncludingDiscontinuedOperationStraightLineRevenueReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_unit_DisposalGroupIncludingDiscontinuedOperationStraightLineRevenueReceivable_e00eda0f-2e63-4cb8-8a8d-bfa3f7972a59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_05141466-40c8-4699-b6c4-d84b3e5c69fc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_05141466-40c8-4699-b6c4-d84b3e5c69fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities_d9a206c3-1220-4d40-a532-5f3af3daab74" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationAccountsPayableAndAccruedLiabilities_d9a206c3-1220-4d40-a532-5f3af3daab74" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenue_1f4003cf-473f-4098-9acc-8e6f39184e20" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationDeferredRevenue_1f4003cf-473f-4098-9acc-8e6f39184e20" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_08191f41-398e-47b3-9492-5b007a06a585" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_578c4aa8-b7e5-428f-8c31-5b6c77d2026e" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperation_08191f41-398e-47b3-9492-5b007a06a585" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/FairValueofFinancialInstrumentsScheduleofFairValueValuationofFinancialInstrumentsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#FairValueofFinancialInstrumentsScheduleofFairValueValuationofFinancialInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/FairValueofFinancialInstrumentsScheduleofFairValueValuationofFinancialInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_28e43d3f-9cb8-4050-b795-30bb333eee28" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8930b613-0fba-4756-9b28-3142f919b3e7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_28e43d3f-9cb8-4050-b795-30bb333eee28" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8930b613-0fba-4756-9b28-3142f919b3e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238c8493-313d-466c-941d-c5e8ad7c7504" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8930b613-0fba-4756-9b28-3142f919b3e7" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238c8493-313d-466c-941d-c5e8ad7c7504" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_238c8493-313d-466c-941d-c5e8ad7c7504_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238c8493-313d-466c-941d-c5e8ad7c7504" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_238c8493-313d-466c-941d-c5e8ad7c7504_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bed1573-9191-4f8d-a3ab-35489a6fe153" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_238c8493-313d-466c-941d-c5e8ad7c7504" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bed1573-9191-4f8d-a3ab-35489a6fe153" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_cb205c4c-0b89-4859-bedf-fc24f0ddb7c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bed1573-9191-4f8d-a3ab-35489a6fe153" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_cb205c4c-0b89-4859-bedf-fc24f0ddb7c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_7913904d-854e-45d2-a4ee-e4437b7600d5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bed1573-9191-4f8d-a3ab-35489a6fe153" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_7913904d-854e-45d2-a4ee-e4437b7600d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_6767210c-9924-4f83-aa00-5d423a424699" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3bed1573-9191-4f8d-a3ab-35489a6fe153" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_6767210c-9924-4f83-aa00-5d423a424699" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_480566e6-e0a7-493c-9744-76b589b8c369" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_8930b613-0fba-4756-9b28-3142f919b3e7" xlink:to="loc_us-gaap_DebtInstrumentAxis_480566e6-e0a7-493c-9744-76b589b8c369" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_480566e6-e0a7-493c-9744-76b589b8c369_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_480566e6-e0a7-493c-9744-76b589b8c369" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_480566e6-e0a7-493c-9744-76b589b8c369_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_480566e6-e0a7-493c-9744-76b589b8c369" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_d934f7f7-8d1a-4d26-a863-7d786774ea27" xlink:href="unit-20241231.xsd#unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_d934f7f7-8d1a-4d26-a863-7d786774ea27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_3628488d-f1f7-4dd9-a89b-1500d9be58ba" xlink:href="unit-20241231.xsd#unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_3628488d-f1f7-4dd9-a89b-1500d9be58ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_d2f4aa91-2ed0-4503-a629-0aaecaea93c9" xlink:href="unit-20241231.xsd#unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_d2f4aa91-2ed0-4503-a629-0aaecaea93c9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_5f5aa22a-6085-4941-8db7-36aba8801a30" xlink:href="unit-20241231.xsd#unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_5f5aa22a-6085-4941-8db7-36aba8801a30" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember_cdff2154-a091-448c-9c16-8921ffd0eba2" xlink:href="unit-20241231.xsd#unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember_cdff2154-a091-448c-9c16-8921ffd0eba2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_a3896c13-0d16-4dcd-8a17-0c8cef9446d5" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_a3896c13-0d16-4dcd-8a17-0c8cef9446d5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSCreditAgreementMember_61778678-bb3f-4750-8631-efd05731597c" xlink:href="unit-20241231.xsd#unit_ABSCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_ABSCreditAgreementMember_61778678-bb3f-4750-8631-efd05731597c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_41200dbe-1fe9-4ab7-84c0-3cdbebd7e4d8" xlink:href="unit-20241231.xsd#unit_SeniorSecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_442660eb-a0ba-428e-851a-0cd8a56e4ac6" xlink:to="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_41200dbe-1fe9-4ab7-84c0-3cdbebd7e4d8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_b59f5b2e-03cb-4f15-9713-8fc5d11a0d83" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_28e43d3f-9cb8-4050-b795-30bb333eee28" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_b59f5b2e-03cb-4f15-9713-8fc5d11a0d83" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_e8d1802c-d09e-4b5c-8589-a39f1592ad2f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_b59f5b2e-03cb-4f15-9713-8fc5d11a0d83" xlink:to="loc_us-gaap_DerivativeAssets_e8d1802c-d09e-4b5c-8589-a39f1592ad2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_6c2ff3c9-c85c-448f-9046-542b2d96445c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_b59f5b2e-03cb-4f15-9713-8fc5d11a0d83" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_6c2ff3c9-c85c-448f-9046-542b2d96445c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_28e43d3f-9cb8-4050-b795-30bb333eee28" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_0635b7f4-fdc6-42f8-88a6-48ceadece428" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_0635b7f4-fdc6-42f8-88a6-48ceadece428" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditFairValueDisclosure_d26971bd-f8e5-4229-a638-05ae034401c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LinesOfCreditFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:to="loc_us-gaap_LinesOfCreditFairValueDisclosure_d26971bd-f8e5-4229-a638-05ae034401c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SettlementPayableFairValueDisclosure_83b2d928-2e18-47fd-9259-4cccb3310bf8" xlink:href="unit-20241231.xsd#unit_SettlementPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:to="loc_unit_SettlementPayableFairValueDisclosure_83b2d928-2e18-47fd-9259-4cccb3310bf8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_84b01c6b-caee-4793-9df2-16deb71d50e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_b812e549-e153-4d58-8ba1-fcbd76830fe0" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosure_84b01c6b-caee-4793-9df2-16deb71d50e4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_26620ddd-a9f3-42bd-8ab0-55a631cf6097" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_28e43d3f-9cb8-4050-b795-30bb333eee28" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_26620ddd-a9f3-42bd-8ab0-55a631cf6097" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/FairValueofFinancialInstrumentsAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#FairValueofFinancialInstrumentsAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/FairValueofFinancialInstrumentsAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_627ac44b-5130-4e3e-969b-7734e5a8579a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_627ac44b-5130-4e3e-969b-7734e5a8579a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_705e1f1b-4b0f-4427-b91b-d119e32709c4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_627ac44b-5130-4e3e-969b-7734e5a8579a" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_705e1f1b-4b0f-4427-b91b-d119e32709c4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_705e1f1b-4b0f-4427-b91b-d119e32709c4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_705e1f1b-4b0f-4427-b91b-d119e32709c4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_705e1f1b-4b0f-4427-b91b-d119e32709c4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c44dc494-c2f0-416a-bab1-a686931c51d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_705e1f1b-4b0f-4427-b91b-d119e32709c4" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c44dc494-c2f0-416a-bab1-a686931c51d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_50db941f-a4eb-4193-8341-d67a70addc46" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_c44dc494-c2f0-416a-bab1-a686931c51d9" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_50db941f-a4eb-4193-8341-d67a70addc46" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsAxis_e3f06a1a-28b7-4535-baa5-3362634344c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_627ac44b-5130-4e3e-969b-7734e5a8579a" xlink:to="loc_us-gaap_OtherCommitmentsAxis_e3f06a1a-28b7-4535-baa5-3362634344c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_e3f06a1a-28b7-4535-baa5-3362634344c6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherCommitmentsAxis_e3f06a1a-28b7-4535-baa5-3362634344c6" xlink:to="loc_us-gaap_OtherCommitmentsDomain_e3f06a1a-28b7-4535-baa5-3362634344c6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitmentsDomain_62dc8420-e0d8-4206-98de-d99f4778d95b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitmentsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherCommitmentsAxis_e3f06a1a-28b7-4535-baa5-3362634344c6" xlink:to="loc_us-gaap_OtherCommitmentsDomain_62dc8420-e0d8-4206-98de-d99f4778d95b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamCommitmentMember_f619f612-c63c-47c4-8205-df6c451a9873" xlink:href="unit-20241231.xsd#unit_WindstreamCommitmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherCommitmentsDomain_62dc8420-e0d8-4206-98de-d99f4778d95b" xlink:to="loc_unit_WindstreamCommitmentMember_f619f612-c63c-47c4-8205-df6c451a9873" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_417eef8c-0c59-45da-ba01-78efbcc27d49" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_417eef8c-0c59-45da-ba01-78efbcc27d49" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_8aadcbd8-0e6d-4f65-b33a-da2da62463d6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_us-gaap_LongTermDebtFairValue_8aadcbd8-0e6d-4f65-b33a-da2da62463d6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCommitment_f3c3eca2-9ea5-44d3-8be8-1a8ec7e8d932" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCommitment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_us-gaap_OtherCommitment_f3c3eca2-9ea5-44d3-8be8-1a8ec7e8d932" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OtherCommitmentNumberOfInstallments_3828239e-7fce-47af-a5a6-c67737e5d756" xlink:href="unit-20241231.xsd#unit_OtherCommitmentNumberOfInstallments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_unit_OtherCommitmentNumberOfInstallments_3828239e-7fce-47af-a5a6-c67737e5d756" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SettlementPayable_97c40c7b-8623-42f5-a539-216ed2fe29e0" xlink:href="unit-20241231.xsd#unit_SettlementPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_f1dc866c-969f-4a95-b8c7-9c3be1f69bfa" xlink:to="loc_unit_SettlementPayable_97c40c7b-8623-42f5-a539-216ed2fe29e0" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/PropertyPlantandEquipmentScheduleofCarryingValueofPropertyPlantandEquipmentDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#PropertyPlantandEquipmentScheduleofCarryingValueofPropertyPlantandEquipmentDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/PropertyPlantandEquipmentScheduleofCarryingValueofPropertyPlantandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_821d16e9-70fd-483d-bc01-8d284281f05f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_821d16e9-70fd-483d-bc01-8d284281f05f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1359aadb-72bb-4159-9782-8175fe66ec93" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_821d16e9-70fd-483d-bc01-8d284281f05f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1359aadb-72bb-4159-9782-8175fe66ec93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1359aadb-72bb-4159-9782-8175fe66ec93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1359aadb-72bb-4159-9782-8175fe66ec93" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_1359aadb-72bb-4159-9782-8175fe66ec93_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_1359aadb-72bb-4159-9782-8175fe66ec93" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_c1946682-3df5-4aac-b153-9967defd0404" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_us-gaap_LandMember_c1946682-3df5-4aac-b153-9967defd0404" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_709a6dc4-11ad-4723-b04b-993f534f3311" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_709a6dc4-11ad-4723-b04b-993f534f3311" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PolesMember_8a554828-cf25-46a3-b12d-25279385a916" xlink:href="unit-20241231.xsd#unit_PolesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_PolesMember_8a554828-cf25-46a3-b12d-25279385a916" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberMember_c73370dd-6377-4ee0-9ac5-4add62f56eae" xlink:href="unit-20241231.xsd#unit_FiberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_FiberMember_c73370dd-6377-4ee0-9ac5-4add62f56eae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_79dd0fcc-e9f0-4f20-8f41-076b35a1e672" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_us-gaap_EquipmentMember_79dd0fcc-e9f0-4f20-8f41-076b35a1e672" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CopperMember_510c0b6c-6c20-4024-b7dd-c15f6901246c" xlink:href="unit-20241231.xsd#unit_CopperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_CopperMember_510c0b6c-6c20-4024-b7dd-c15f6901246c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConduitMember_3806cc59-5fef-44ee-83e2-4a2cb451790a" xlink:href="unit-20241231.xsd#unit_ConduitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_ConduitMember_3806cc59-5fef-44ee-83e2-4a2cb451790a" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TowerAssetsMember_642618c0-75f4-4121-868d-40a9e6c0b0ea" xlink:href="unit-20241231.xsd#unit_TowerAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_TowerAssetsMember_642618c0-75f4-4121-868d-40a9e6c0b0ea" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FinanceLeaseAssetsMember_ad0bec86-82ef-4a86-8410-956ba50bc10b" xlink:href="unit-20241231.xsd#unit_FinanceLeaseAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_FinanceLeaseAssetsMember_ad0bec86-82ef-4a86-8410-956ba50bc10b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_f7a2527e-424b-4906-bb3e-73904b6435b1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_f7a2527e-424b-4906-bb3e-73904b6435b1" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_b3c918ea-1e6f-4125-88f2-40d32913d7b5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_us-gaap_ConstructionInProgressMember_b3c918ea-1e6f-4125-88f2-40d32913d7b5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CorporateAssetsMember_e4d98dcf-3e68-415b-9c5d-d6fc18affda8" xlink:href="unit-20241231.xsd#unit_CorporateAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6849db42-df79-4103-8196-90924ead7bc0" xlink:to="loc_unit_CorporateAssetsMember_e4d98dcf-3e68-415b-9c5d-d6fc18affda8" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_f7a5dc73-376c-49c1-8d46-1838a6034dc9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_821d16e9-70fd-483d-bc01-8d284281f05f" xlink:to="loc_srt_RangeAxis_f7a5dc73-376c-49c1-8d46-1838a6034dc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_f7a5dc73-376c-49c1-8d46-1838a6034dc9_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_f7a5dc73-376c-49c1-8d46-1838a6034dc9" xlink:to="loc_srt_RangeMember_f7a5dc73-376c-49c1-8d46-1838a6034dc9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4ee5021c-4dc8-4a30-b164-f80ab2fa140a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_f7a5dc73-376c-49c1-8d46-1838a6034dc9" xlink:to="loc_srt_RangeMember_4ee5021c-4dc8-4a30-b164-f80ab2fa140a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_4acee595-7ac4-426f-ae23-fc428858d104" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4ee5021c-4dc8-4a30-b164-f80ab2fa140a" xlink:to="loc_srt_MinimumMember_4acee595-7ac4-426f-ae23-fc428858d104" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_58772d92-04fa-467c-89df-46aef5f82dd3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_4ee5021c-4dc8-4a30-b164-f80ab2fa140a" xlink:to="loc_srt_MaximumMember_58772d92-04fa-467c-89df-46aef5f82dd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_325f4a0a-026b-49ad-90b0-198fc26b8df0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_821d16e9-70fd-483d-bc01-8d284281f05f" xlink:to="loc_srt_MajorCustomersAxis_325f4a0a-026b-49ad-90b0-198fc26b8df0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_325f4a0a-026b-49ad-90b0-198fc26b8df0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_325f4a0a-026b-49ad-90b0-198fc26b8df0" xlink:to="loc_srt_NameOfMajorCustomerDomain_325f4a0a-026b-49ad-90b0-198fc26b8df0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_eb4cd251-ddc0-4f32-9ea1-adbff73bd4ef" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_325f4a0a-026b-49ad-90b0-198fc26b8df0" xlink:to="loc_srt_NameOfMajorCustomerDomain_eb4cd251-ddc0-4f32-9ea1-adbff73bd4ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_420fbe06-b0ee-491c-b1d8-7f330dc32ee6" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_eb4cd251-ddc0-4f32-9ea1-adbff73bd4ef" xlink:to="loc_unit_WindstreamMember_420fbe06-b0ee-491c-b1d8-7f330dc32ee6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_478e2014-310f-4e7d-989f-5bb09d7e181f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_478e2014-310f-4e7d-989f-5bb09d7e181f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_4d57637a-6cb7-4906-b1c1-b730d1e6a2b5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_4d57637a-6cb7-4906-b1c1-b730d1e6a2b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_e1ce54ed-929c-415c-92e3-ba00b66228c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetBeforeAccumulatedAmortization_e1ce54ed-929c-415c-92e3-ba00b66228c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_6c52d3f4-b957-444a-9824-891be8b9a77d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_6c52d3f4-b957-444a-9824-891be8b9a77d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_f7471b5f-e2c7-4a56-a6cc-e4034b0b3311" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_f7471b5f-e2c7-4a56-a6cc-e4034b0b3311" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_276d1699-734a-4990-896e-4358be0ec94a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_55a1392e-9658-4ed3-a431-9062ed81bfd5" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_276d1699-734a-4990-896e-4358be0ec94a" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesNarrativeDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#DerivativeInstrumentsandHedgingActivitiesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_54d0afe1-7c34-482e-816f-07209d75bcbe" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_9c07283f-4d7b-4d7b-9f6d-cfa1fc2177d0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_54d0afe1-7c34-482e-816f-07209d75bcbe" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_9c07283f-4d7b-4d7b-9f6d-cfa1fc2177d0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_9826c905-eebb-4cee-85c4-e5ab228d026e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_9c07283f-4d7b-4d7b-9f6d-cfa1fc2177d0" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_9826c905-eebb-4cee-85c4-e5ab228d026e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_9826c905-eebb-4cee-85c4-e5ab228d026e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9826c905-eebb-4cee-85c4-e5ab228d026e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_9826c905-eebb-4cee-85c4-e5ab228d026e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_1598b468-80a5-481d-9314-178263557578" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_9826c905-eebb-4cee-85c4-e5ab228d026e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_1598b468-80a5-481d-9314-178263557578" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_717b9663-d46d-44fb-bece-e9298dd6ce2f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_1598b468-80a5-481d-9314-178263557578" xlink:to="loc_us-gaap_InterestRateCapMember_717b9663-d46d-44fb-bece-e9298dd6ce2f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_ea026aaa-0706-4744-af73-1675e3327d42" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_9c07283f-4d7b-4d7b-9f6d-cfa1fc2177d0" xlink:to="loc_us-gaap_HedgingDesignationAxis_ea026aaa-0706-4744-af73-1675e3327d42" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_ea026aaa-0706-4744-af73-1675e3327d42_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_ea026aaa-0706-4744-af73-1675e3327d42" xlink:to="loc_us-gaap_HedgingDesignationDomain_ea026aaa-0706-4744-af73-1675e3327d42_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_f8be295f-0ef0-434b-9973-0c6cfe32f960" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_ea026aaa-0706-4744-af73-1675e3327d42" xlink:to="loc_us-gaap_HedgingDesignationDomain_f8be295f-0ef0-434b-9973-0c6cfe32f960" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_ecc23782-b789-4d31-8281-45943309ae3d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_f8be295f-0ef0-434b-9973-0c6cfe32f960" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_ecc23782-b789-4d31-8281-45943309ae3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_67b6bb2a-3e3f-4606-8d7c-50474043f5a2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_54d0afe1-7c34-482e-816f-07209d75bcbe" xlink:to="loc_us-gaap_DerivativeNotionalAmount_67b6bb2a-3e3f-4606-8d7c-50474043f5a2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeCapInterestRate_3effb0e3-55c6-47ed-89c1-e50fec362d82" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeCapInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_54d0afe1-7c34-482e-816f-07209d75bcbe" xlink:to="loc_us-gaap_DerivativeCapInterestRate_3effb0e3-55c6-47ed-89c1-e50fec362d82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_a295e499-67dd-4eac-a957-2e463eec996b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_54d0afe1-7c34-482e-816f-07209d75bcbe" xlink:to="loc_us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_a295e499-67dd-4eac-a957-2e463eec996b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesScheduleofDerivativesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#DerivativeInstrumentsandHedgingActivitiesScheduleofDerivativesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesScheduleofDerivativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_13a2ad10-f532-4eb1-b53e-1a21f2498601" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_8097ed07-7584-43c4-8a3a-b64d7de40883" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_13a2ad10-f532-4eb1-b53e-1a21f2498601" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_8097ed07-7584-43c4-8a3a-b64d7de40883" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_53381365-2956-49e0-8b9e-6f1a23f5fede" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_8097ed07-7584-43c4-8a3a-b64d7de40883" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_53381365-2956-49e0-8b9e-6f1a23f5fede" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_53381365-2956-49e0-8b9e-6f1a23f5fede_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_53381365-2956-49e0-8b9e-6f1a23f5fede" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_53381365-2956-49e0-8b9e-6f1a23f5fede_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_36fd1d38-2574-47da-9750-6de75eb683f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_53381365-2956-49e0-8b9e-6f1a23f5fede" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_36fd1d38-2574-47da-9750-6de75eb683f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_cda88b67-f97c-485e-a134-20b68b5c693b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_36fd1d38-2574-47da-9750-6de75eb683f1" xlink:to="loc_us-gaap_InterestRateCapMember_cda88b67-f97c-485e-a134-20b68b5c693b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_8097ed07-7584-43c4-8a3a-b64d7de40883" xlink:to="loc_us-gaap_HedgingDesignationAxis_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8" xlink:to="loc_us-gaap_HedgingDesignationDomain_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_9364d205-c142-4099-9e63-45050850433e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_8aaf2d49-3d03-4035-b8a8-43fe3122d2c8" xlink:to="loc_us-gaap_HedgingDesignationDomain_9364d205-c142-4099-9e63-45050850433e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_1e0b4ecd-668d-4e1f-a661-d68f7f774a7a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_9364d205-c142-4099-9e63-45050850433e" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_1e0b4ecd-668d-4e1f-a661-d68f7f774a7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_c496f231-70f1-4581-8784-c8a81f7e1f40" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_13a2ad10-f532-4eb1-b53e-1a21f2498601" xlink:to="loc_us-gaap_DerivativeAssets_c496f231-70f1-4581-8784-c8a81f7e1f40" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesScheduleofCashFlowHedgesonCondensedConsolidatedStatementsofIncomeLossDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#DerivativeInstrumentsandHedgingActivitiesScheduleofCashFlowHedgesonCondensedConsolidatedStatementsofIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/DerivativeInstrumentsandHedgingActivitiesScheduleofCashFlowHedgesonCondensedConsolidatedStatementsofIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_0b8b2ad7-c2c2-402f-84a1-7beb11598f39" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_72032d58-d4b2-420a-8835-cb65ddb0c527" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_0b8b2ad7-c2c2-402f-84a1-7beb11598f39" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_72032d58-d4b2-420a-8835-cb65ddb0c527" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_d24d2e7d-4955-4b77-b6e1-51851b61e554" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_72032d58-d4b2-420a-8835-cb65ddb0c527" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_d24d2e7d-4955-4b77-b6e1-51851b61e554" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_d24d2e7d-4955-4b77-b6e1-51851b61e554_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_d24d2e7d-4955-4b77-b6e1-51851b61e554" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_d24d2e7d-4955-4b77-b6e1-51851b61e554_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_9f5cd8c7-bd95-46c5-a676-467a026bd3e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_d24d2e7d-4955-4b77-b6e1-51851b61e554" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_9f5cd8c7-bd95-46c5-a676-467a026bd3e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_e4787d40-962c-403b-877c-2dca626e8888" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_9f5cd8c7-bd95-46c5-a676-467a026bd3e4" xlink:to="loc_us-gaap_InterestRateCapMember_e4787d40-962c-403b-877c-2dca626e8888" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_cb6cfb66-0ff5-49fe-8471-4ba15e8b096f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_0b8b2ad7-c2c2-402f-84a1-7beb11598f39" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_cb6cfb66-0ff5-49fe-8471-4ba15e8b096f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_928594f3-a9e4-49d2-b347-a9d2915456ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_0b8b2ad7-c2c2-402f-84a1-7beb11598f39" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_928594f3-a9e4-49d2-b347-a9d2915456ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNet_97233c83-1400-4295-af2e-6cd2691ac233" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_0b8b2ad7-c2c2-402f-84a1-7beb11598f39" xlink:to="loc_us-gaap_InterestIncomeExpenseNet_97233c83-1400-4295-af2e-6cd2691ac233" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/GoodwillandIntangibleAssetsScheduleofCarryingAmountofGoodwillDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#GoodwillandIntangibleAssetsScheduleofCarryingAmountofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/GoodwillandIntangibleAssetsScheduleofCarryingAmountofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_116f3500-429f-4a81-b6e7-fb3562923073" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_40213c0b-817e-42a9-823a-695f56bc4a25" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_116f3500-429f-4a81-b6e7-fb3562923073" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_40213c0b-817e-42a9-823a-695f56bc4a25" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9deb6fc1-e484-40e3-954e-03d7c231249e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_40213c0b-817e-42a9-823a-695f56bc4a25" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9deb6fc1-e484-40e3-954e-03d7c231249e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9deb6fc1-e484-40e3-954e-03d7c231249e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9deb6fc1-e484-40e3-954e-03d7c231249e" xlink:to="loc_us-gaap_SegmentDomain_9deb6fc1-e484-40e3-954e-03d7c231249e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_df0f960e-b937-4481-a2ea-6d2faa5f2fc1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9deb6fc1-e484-40e3-954e-03d7c231249e" xlink:to="loc_us-gaap_SegmentDomain_df0f960e-b937-4481-a2ea-6d2faa5f2fc1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberInfrastructureSegmentMember_55bd37e1-b52d-4d3f-90db-e16a49e956dd" xlink:href="unit-20241231.xsd#unit_FiberInfrastructureSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_df0f960e-b937-4481-a2ea-6d2faa5f2fc1" xlink:to="loc_unit_FiberInfrastructureSegmentMember_55bd37e1-b52d-4d3f-90db-e16a49e956dd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillGross_d2c80e96-723c-4878-9140-b4137808a63d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_116f3500-429f-4a81-b6e7-fb3562923073" xlink:to="loc_us-gaap_GoodwillGross_d2c80e96-723c-4878-9140-b4137808a63d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_cd826e32-1489-4d72-b6a2-7568ce506ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_116f3500-429f-4a81-b6e7-fb3562923073" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_cd826e32-1489-4d72-b6a2-7568ce506ae1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_14472491-e7cb-4698-bdfb-088067eecb35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_116f3500-429f-4a81-b6e7-fb3562923073" xlink:to="loc_us-gaap_GoodwillRollForward_14472491-e7cb-4698-bdfb-088067eecb35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_2c11ca02-255a-4752-867c-655822c83fac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_14472491-e7cb-4698-bdfb-088067eecb35" xlink:to="loc_us-gaap_Goodwill_2c11ca02-255a-4752-867c-655822c83fac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_183d3f67-f536-4a81-8929-8735eaf95a5c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_14472491-e7cb-4698-bdfb-088067eecb35" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_183d3f67-f536-4a81-8929-8735eaf95a5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_73ef0263-7438-4040-ab54-700f65f9a2df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/GoodwillandIntangibleAssetsScheduleofCarryingValueofOtherIntangibleAssetsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#GoodwillandIntangibleAssetsScheduleofCarryingValueofOtherIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/GoodwillandIntangibleAssetsScheduleofCarryingValueofOtherIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:href="unit-20241231.xsd#unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_17339cee-b0ee-4cd3-ab82-ecdf5cd777e9" xlink:href="unit-20241231.xsd#unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_17339cee-b0ee-4cd3-ab82-ecdf5cd777e9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b0dec01a-db3f-4882-8bc9-1c6d0fd51345" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_17339cee-b0ee-4cd3-ab82-ecdf5cd777e9" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b0dec01a-db3f-4882-8bc9-1c6d0fd51345" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b0dec01a-db3f-4882-8bc9-1c6d0fd51345_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b0dec01a-db3f-4882-8bc9-1c6d0fd51345" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b0dec01a-db3f-4882-8bc9-1c6d0fd51345_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_b0dec01a-db3f-4882-8bc9-1c6d0fd51345" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerListsMember_3dd96b3b-b3a5-403e-bf7a-bc1cff3a64ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerListsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:to="loc_us-gaap_CustomerListsMember_3dd96b3b-b3a5-403e-bf7a-bc1cff3a64ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerContractsMember_141085c6-269b-4f02-8a88-62f0d8247c27" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:to="loc_us-gaap_CustomerContractsMember_141085c6-269b-4f02-8a88-62f0d8247c27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnderlyingRightsMember_380fe86e-3b9a-4627-a0b4-d14b019bed4f" xlink:href="unit-20241231.xsd#unit_UnderlyingRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:to="loc_unit_UnderlyingRightsMember_380fe86e-3b9a-4627-a0b4-d14b019bed4f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_BelowMarketLeasesMember_2a456daa-411b-4a15-91e9-3edb6562376c" xlink:href="unit-20241231.xsd#unit_BelowMarketLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_b3096dda-1490-4222-b282-f73a20b6aafa" xlink:to="loc_unit_BelowMarketLeasesMember_2a456daa-411b-4a15-91e9-3edb6562376c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_582ea1a9-9d6e-440e-a685-befa2950e047" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_582ea1a9-9d6e-440e-a685-befa2950e047" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_a3f0251c-9631-4517-947f-3e1cebc308f7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_a3f0251c-9631-4517-947f-3e1cebc308f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_2cd6a944-2beb-477a-b720-bbc4585d4847" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_2cd6a944-2beb-477a-b720-bbc4585d4847" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_dcdd8c1d-8311-4b12-a3c6-59902a99ba36" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_dcdd8c1d-8311-4b12-a3c6-59902a99ba36" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiniteLivedIntangibleLiabilitiesGross_1fad0c4f-d35c-481b-8e01-397a46aab4c5" xlink:href="unit-20241231.xsd#unit_FiniteLivedIntangibleLiabilitiesGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_unit_FiniteLivedIntangibleLiabilitiesGross_1fad0c4f-d35c-481b-8e01-397a46aab4c5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization_6e9d92be-1fef-4920-a875-6712872e4bb6" xlink:href="unit-20241231.xsd#unit_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_unit_FiniteLivedIntangibleLiabilitiesAccumulatedAmortization_6e9d92be-1fef-4920-a875-6712872e4bb6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiniteLivedIntangibleLiabilitiesNet_f94a9315-b5e6-453b-aeb5-48b1f7f401a5" xlink:href="unit-20241231.xsd#unit_FiniteLivedIntangibleLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_627e3fdc-a793-4dcd-ac0c-767ddfcec952" xlink:to="loc_unit_FiniteLivedIntangibleLiabilitiesNet_f94a9315-b5e6-453b-aeb5-48b1f7f401a5" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/GoodwillandIntangibleAssetsAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#GoodwillandIntangibleAssetsAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/GoodwillandIntangibleAssetsAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:href="unit-20241231.xsd#unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_ffeb7cda-7c6e-40e0-adab-5b6add50546f" xlink:href="unit-20241231.xsd#unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_ffeb7cda-7c6e-40e0-adab-5b6add50546f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7da63fca-c86a-49be-9991-ba622b1c2060" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesTable_ffeb7cda-7c6e-40e0-adab-5b6add50546f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7da63fca-c86a-49be-9991-ba622b1c2060" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7da63fca-c86a-49be-9991-ba622b1c2060_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7da63fca-c86a-49be-9991-ba622b1c2060" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_7da63fca-c86a-49be-9991-ba622b1c2060_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8f0cafa-4db9-4138-aa2e-bf295c1d4997" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_7da63fca-c86a-49be-9991-ba622b1c2060" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8f0cafa-4db9-4138-aa2e-bf295c1d4997" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerListsMember_f8d342cc-4613-49fa-b384-393c56fae02b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerListsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8f0cafa-4db9-4138-aa2e-bf295c1d4997" xlink:to="loc_us-gaap_CustomerListsMember_f8d342cc-4613-49fa-b384-393c56fae02b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerContractsMember_f4da74c0-82d0-4b02-a29b-809f93b1d8e3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CustomerContractsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8f0cafa-4db9-4138-aa2e-bf295c1d4997" xlink:to="loc_us-gaap_CustomerContractsMember_f4da74c0-82d0-4b02-a29b-809f93b1d8e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnderlyingRightsMember_c4c5ca7e-88d5-4e14-8f26-c32c2221cf21" xlink:href="unit-20241231.xsd#unit_UnderlyingRightsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a8f0cafa-4db9-4138-aa2e-bf295c1d4997" xlink:to="loc_unit_UnderlyingRightsMember_c4c5ca7e-88d5-4e14-8f26-c32c2221cf21" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_d31d18d8-92cc-4632-878d-eefdb4665e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1_d31d18d8-92cc-4632-878d-eefdb4665e5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_58ae56de-6e66-4ec0-913c-f59fb6123877" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_58ae56de-6e66-4ec0-913c-f59fb6123877" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_5ae9029f-50ac-474f-a0dc-c5852c3808d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths_5ae9029f-50ac-474f-a0dc-c5852c3808d1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_510b9f69-4b87-47b5-bc17-7b05d2e72e8b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo_510b9f69-4b87-47b5-bc17-7b05d2e72e8b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_fcec9ae9-5dfb-4507-82df-f1edab76a45c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree_fcec9ae9-5dfb-4507-82df-f1edab76a45c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_c58ae352-de88-482c-8e86-c765d6ec822c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_c58ae352-de88-482c-8e86-c765d6ec822c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ecc5905d-5b80-45c9-8fab-d5638ff107dc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive_ecc5905d-5b80-45c9-8fab-d5638ff107dc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfBelowMarketLease_9563a93f-174f-485e-aa0f-399abba7a5fd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AmortizationOfBelowMarketLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_AmortizationOfBelowMarketLease_9563a93f-174f-485e-aa0f-399abba7a5fd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiniteLivedIntangibleLiabilitiesRemainingAmortizationPeriod_aea287db-0fc1-42a6-8457-78b99d6be7a8" xlink:href="unit-20241231.xsd#unit_FiniteLivedIntangibleLiabilitiesRemainingAmortizationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_unit_FiniteLivedIntangibleLiabilitiesRemainingAmortizationPeriod_aea287db-0fc1-42a6-8457-78b99d6be7a8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths_b5854ec6-e50c-4c61-8811-c2cf50c96041" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeNextTwelveMonths_b5854ec6-e50c-4c61-8811-c2cf50c96041" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo_230d599c-aa51-4da3-bebc-7d4e297d6191" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearTwo_230d599c-aa51-4da3-bebc-7d4e297d6191" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearThree_ef9bca70-1762-482d-a7b8-558cfcbd61eb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearThree_ef9bca70-1762-482d-a7b8-558cfcbd61eb" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFour_cc0947ae-395b-4de2-b2b2-d1199e3d3904" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFour_cc0947ae-395b-4de2-b2b2-d1199e3d3904" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFive_902d1b9d-f96d-48a2-917c-772640e99ded" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BelowMarketLeaseAmortizationIncomeYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ScheduleOfIndefiniteAndFiniteLivedIntangibleAssetsAndLiabilitiesLineItems_ad2fd9c9-8ae2-4c15-a9a3-700358dd17e3" xlink:to="loc_us-gaap_BelowMarketLeaseAmortizationIncomeYearFive_902d1b9d-f96d-48a2-917c-772640e99ded" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/NotesandOtherDebtScheduleofNotesandOtherDebtDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#NotesandOtherDebtScheduleofNotesandOtherDebtDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/NotesandOtherDebtScheduleofNotesandOtherDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_77e379b7-b7fc-49a6-ae12-a357c54b98d6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_DebtInstrumentTable_77e379b7-b7fc-49a6-ae12-a357c54b98d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_83ec4b10-8dc1-48ca-80c9-5bbb83802a62" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_77e379b7-b7fc-49a6-ae12-a357c54b98d6" xlink:to="loc_us-gaap_DebtInstrumentAxis_83ec4b10-8dc1-48ca-80c9-5bbb83802a62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_83ec4b10-8dc1-48ca-80c9-5bbb83802a62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_83ec4b10-8dc1-48ca-80c9-5bbb83802a62" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_83ec4b10-8dc1-48ca-80c9-5bbb83802a62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_83ec4b10-8dc1-48ca-80c9-5bbb83802a62" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_75ebd1ab-ff0c-44cb-b39c-4d2fb6b032c6" xlink:href="unit-20241231.xsd#unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_75ebd1ab-ff0c-44cb-b39c-4d2fb6b032c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_cb4e087c-92ca-463e-af19-e00ef72a1122" xlink:href="unit-20241231.xsd#unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_cb4e087c-92ca-463e-af19-e00ef72a1122" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_3ee632d9-e14f-45b2-9509-312db59a1752" xlink:href="unit-20241231.xsd#unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_3ee632d9-e14f-45b2-9509-312db59a1752" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointZeroPercentageSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_c7b0ce45-c5b1-490e-8325-add6276ba627" xlink:href="unit-20241231.xsd#unit_SixPointZeroPercentageSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandThirtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_SixPointZeroPercentageSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_c7b0ce45-c5b1-490e-8325-add6276ba627" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember_8b16f21a-92c9-4b85-92bc-bf2f9ad0a9a3" xlink:href="unit-20241231.xsd#unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_FourPercentageExchangeableSeniorUnsecuredNotesDueJuneFifteenTwoThousandTwentyFourMember_8b16f21a-92c9-4b85-92bc-bf2f9ad0a9a3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_062b9665-9493-4782-9dbf-cc7cb93b12d6" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_062b9665-9493-4782-9dbf-cc7cb93b12d6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSLoanFacilityMember_6097b07f-6dae-4aa0-a32f-6f4a77b9aa22" xlink:href="unit-20241231.xsd#unit_ABSLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_ABSLoanFacilityMember_6097b07f-6dae-4aa0-a32f-6f4a77b9aa22" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_1174eb14-0a52-4c5c-8cd6-89179be3828a" xlink:href="unit-20241231.xsd#unit_SeniorSecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_caf063e1-a82f-4019-a514-b0c3118b5d49" xlink:to="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_1174eb14-0a52-4c5c-8cd6-89179be3828a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_cc79c62d-e8d6-4453-9b01-611ffe98c047" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_cc79c62d-e8d6-4453-9b01-611ffe98c047" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_48be4ff2-3cce-4b29-b1e9-33124f652220" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_48be4ff2-3cce-4b29-b1e9-33124f652220" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_89ad75bc-4d09-4fbe-810a-ba6a6861e963" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_LongTermDebt_89ad75bc-4d09-4fbe-810a-ba6a6861e963" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a281172f-f56b-4fad-bad6-2733933250e1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_a281172f-f56b-4fad-bad6-2733933250e1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_b982db4a-dcf4-4b0a-8c9e-e3dce9976938" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9f52860f-cfc9-4a7d-b89a-197dd452ae36" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_b982db4a-dcf4-4b0a-8c9e-e3dce9976938" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/NotesandOtherDebtNotesandOtherDebtNarrativeDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#NotesandOtherDebtNotesandOtherDebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/NotesandOtherDebtNotesandOtherDebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_9e1be15f-32c2-4793-98e2-d3880cd9f15f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_04baca02-9b7b-4a69-ac89-b29aadf8dcc9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9e1be15f-32c2-4793-98e2-d3880cd9f15f" xlink:to="loc_us-gaap_DebtInstrumentTable_04baca02-9b7b-4a69-ac89-b29aadf8dcc9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_4cba587c-787d-49d4-a171-71b6f37bc2a4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_04baca02-9b7b-4a69-ac89-b29aadf8dcc9" xlink:to="loc_us-gaap_DebtInstrumentAxis_4cba587c-787d-49d4-a171-71b6f37bc2a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_4cba587c-787d-49d4-a171-71b6f37bc2a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_4cba587c-787d-49d4-a171-71b6f37bc2a4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_4cba587c-787d-49d4-a171-71b6f37bc2a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_4cba587c-787d-49d4-a171-71b6f37bc2a4" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_ddd1df1f-0298-4eba-986d-92840ef9a3ba" xlink:href="unit-20241231.xsd#unit_SeniorSecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_ddd1df1f-0298-4eba-986d-92840ef9a3ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSLoanFacilityMember_760885b7-e904-46b1-bb54-244d4c544aba" xlink:href="unit-20241231.xsd#unit_ABSLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_ABSLoanFacilityMember_760885b7-e904-46b1-bb54-244d4c544aba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_281f7bdb-4f73-4b35-b817-af0b1bd342e5" xlink:href="unit-20241231.xsd#unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_281f7bdb-4f73-4b35-b817-af0b1bd342e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_00b8e36e-f851-41ac-9c6c-dca4cc8b70f7" xlink:href="unit-20241231.xsd#unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_00b8e36e-f851-41ac-9c6c-dca4cc8b70f7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_6743804c-bf36-4c27-8662-c49224e885fe" xlink:href="unit-20241231.xsd#unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_6743804c-bf36-4c27-8662-c49224e885fe" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_383de0ea-ec92-4999-9da1-600c971baac0" xlink:href="unit-20241231.xsd#unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_SixPointZeroPercentageSeniorSecuredNotesDueJanuaryFifteenTwoThousandThirtyMember_383de0ea-ec92-4999-9da1-600c971baac0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_2df3149a-3439-4ae2-8013-ae406666670d" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_53e8c8c5-8215-4c38-8945-b68d480790a5" xlink:to="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_2df3149a-3439-4ae2-8013-ae406666670d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_171479e1-42f9-42c5-8403-cdd9dea2f92a" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_04baca02-9b7b-4a69-ac89-b29aadf8dcc9" xlink:to="loc_dei_LegalEntityAxis_171479e1-42f9-42c5-8403-cdd9dea2f92a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_171479e1-42f9-42c5-8403-cdd9dea2f92a_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_171479e1-42f9-42c5-8403-cdd9dea2f92a" xlink:to="loc_dei_EntityDomain_171479e1-42f9-42c5-8403-cdd9dea2f92a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_006a2982-069d-4fa9-a7bc-2f8d64c94394" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_171479e1-42f9-42c5-8403-cdd9dea2f92a" xlink:to="loc_dei_EntityDomain_006a2982-069d-4fa9-a7bc-2f8d64c94394" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember_42150800-bf98-486e-b23a-9fc03d43558b" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_006a2982-069d-4fa9-a7bc-2f8d64c94394" xlink:to="loc_unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember_42150800-bf98-486e-b23a-9fc03d43558b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_ba973dac-50ee-4045-8013-c0adc6f5a0ae" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9e1be15f-32c2-4793-98e2-d3880cd9f15f" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_ba973dac-50ee-4045-8013-c0adc6f5a0ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_c6481b9c-4402-4977-a572-d3142b546dcf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_9e1be15f-32c2-4793-98e2-d3880cd9f15f" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_c6481b9c-4402-4977-a572-d3142b546dcf" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/NotesandOtherDebtCreditAgreementNarrativeDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#NotesandOtherDebtCreditAgreementNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/NotesandOtherDebtCreditAgreementNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_5c5c6e5a-210f-4ca3-a01e-254dea48f752" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:to="loc_us-gaap_DebtInstrumentAxis_5c5c6e5a-210f-4ca3-a01e-254dea48f752" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_5c5c6e5a-210f-4ca3-a01e-254dea48f752_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_5c5c6e5a-210f-4ca3-a01e-254dea48f752" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_5c5c6e5a-210f-4ca3-a01e-254dea48f752_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_3e747016-71c7-48c2-87e4-1891a9f4df3d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_5c5c6e5a-210f-4ca3-a01e-254dea48f752" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_3e747016-71c7-48c2-87e4-1891a9f4df3d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ExtendedRevolvingCreditFacilityMember_ea94890b-261b-4c05-ace6-bdd6e3b8fd5d" xlink:href="unit-20241231.xsd#unit_ExtendedRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3e747016-71c7-48c2-87e4-1891a9f4df3d" xlink:to="loc_unit_ExtendedRevolvingCreditFacilityMember_ea94890b-261b-4c05-ace6-bdd6e3b8fd5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_c0c0652c-97fa-4008-ba75-3d5cd933275e" xlink:href="unit-20241231.xsd#unit_SeniorSecuredRevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3e747016-71c7-48c2-87e4-1891a9f4df3d" xlink:to="loc_unit_SeniorSecuredRevolvingCreditFacilityMember_c0c0652c-97fa-4008-ba75-3d5cd933275e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_1561a438-d487-4941-9308-42363e25d9e6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:to="loc_dei_LegalEntityAxis_1561a438-d487-4941-9308-42363e25d9e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_1561a438-d487-4941-9308-42363e25d9e6_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_1561a438-d487-4941-9308-42363e25d9e6" xlink:to="loc_dei_EntityDomain_1561a438-d487-4941-9308-42363e25d9e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_bb16c30d-4778-44ea-af10-91c26c9c9cf6" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_1561a438-d487-4941-9308-42363e25d9e6" xlink:to="loc_dei_EntityDomain_bb16c30d-4778-44ea-af10-91c26c9c9cf6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CSLCapitalLLCMember_32a1192d-092e-46cc-bdda-f0a6853a61cb" xlink:href="unit-20241231.xsd#unit_CSLCapitalLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_bb16c30d-4778-44ea-af10-91c26c9c9cf6" xlink:to="loc_unit_CSLCapitalLLCMember_32a1192d-092e-46cc-bdda-f0a6853a61cb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:to="loc_srt_RangeAxis_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1" xlink:to="loc_srt_RangeMember_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_d3b7df57-6276-442b-ba56-1f60d03c6559" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_3ffc4262-a66a-4d5c-be40-bfe4bc8f7ff1" xlink:to="loc_srt_RangeMember_d3b7df57-6276-442b-ba56-1f60d03c6559" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_eb2fd5b0-b868-4dc2-965d-6938584f5e6f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d3b7df57-6276-442b-ba56-1f60d03c6559" xlink:to="loc_srt_MaximumMember_eb2fd5b0-b868-4dc2-965d-6938584f5e6f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_d48ec3f0-8de5-494c-8f3d-922ecedb52dc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_d3b7df57-6276-442b-ba56-1f60d03c6559" xlink:to="loc_srt_MinimumMember_d48ec3f0-8de5-494c-8f3d-922ecedb52dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_80dc1b68-bea9-4ff5-b716-4dd24c5d991b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:to="loc_us-gaap_VariableRateAxis_80dc1b68-bea9-4ff5-b716-4dd24c5d991b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_80dc1b68-bea9-4ff5-b716-4dd24c5d991b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_80dc1b68-bea9-4ff5-b716-4dd24c5d991b" xlink:to="loc_us-gaap_VariableRateDomain_80dc1b68-bea9-4ff5-b716-4dd24c5d991b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_e0a4659c-c63a-4921-959e-5fe6d5eaf160" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_80dc1b68-bea9-4ff5-b716-4dd24c5d991b" xlink:to="loc_us-gaap_VariableRateDomain_e0a4659c-c63a-4921-959e-5fe6d5eaf160" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_95e8f5a7-7707-4cbc-96c0-05ea29850648" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e0a4659c-c63a-4921-959e-5fe6d5eaf160" xlink:to="loc_us-gaap_BaseRateMember_95e8f5a7-7707-4cbc-96c0-05ea29850648" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_473aaeb7-8728-40cd-b464-fc5364940318" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e0a4659c-c63a-4921-959e-5fe6d5eaf160" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_473aaeb7-8728-40cd-b464-fc5364940318" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_4c741253-4e41-4d1e-a8ff-f721c11b4605" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_fe23636e-3928-4cdf-8dac-ce33cf711ba7" xlink:to="loc_srt_StatementScenarioAxis_4c741253-4e41-4d1e-a8ff-f721c11b4605" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_4c741253-4e41-4d1e-a8ff-f721c11b4605_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_4c741253-4e41-4d1e-a8ff-f721c11b4605" xlink:to="loc_srt_ScenarioUnspecifiedDomain_4c741253-4e41-4d1e-a8ff-f721c11b4605_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_4683f87c-2c8d-46b8-969f-1f4ddce8d01a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_4c741253-4e41-4d1e-a8ff-f721c11b4605" xlink:to="loc_srt_ScenarioUnspecifiedDomain_4683f87c-2c8d-46b8-969f-1f4ddce8d01a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProFormaMember_9cfba347-3844-4592-9fb9-9b335e00594e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ProFormaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_4683f87c-2c8d-46b8-969f-1f4ddce8d01a" xlink:to="loc_srt_ProFormaMember_9cfba347-3844-4592-9fb9-9b335e00594e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_567c7ae8-72f3-4dcc-8335-48abd4833f2e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_567c7ae8-72f3-4dcc-8335-48abd4833f2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DebtInstrumentCovenantSecuredLeverageRatio_0422654d-3613-461e-8271-8e2069a766b7" xlink:href="unit-20241231.xsd#unit_DebtInstrumentCovenantSecuredLeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_unit_DebtInstrumentCovenantSecuredLeverageRatio_0422654d-3613-461e-8271-8e2069a766b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeverageRatio_d9d5316f-556a-4cb5-9c5b-1aec6747bdc7" xlink:href="unit-20241231.xsd#unit_LeverageRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_unit_LeverageRatio_d9d5316f-556a-4cb5-9c5b-1aec6747bdc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDefaultLongtermDebtAmount_3bb9ae28-6df2-4573-9fcd-b2998f47b65e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtDefaultLongtermDebtAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_us-gaap_DebtDefaultLongtermDebtAmount_3bb9ae28-6df2-4573-9fcd-b2998f47b65e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DebtInstrumentCovenantLeaseDefaultPeriodThreshold_af616972-abca-4a3f-a3cc-86b9fb11c5de" xlink:href="unit-20241231.xsd#unit_DebtInstrumentCovenantLeaseDefaultPeriodThreshold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_unit_DebtInstrumentCovenantLeaseDefaultPeriodThreshold_af616972-abca-4a3f-a3cc-86b9fb11c5de" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_07c8361d-0840-46cc-a220-05ad32ef1139" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_07c8361d-0840-46cc-a220-05ad32ef1139" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_6f609fc5-df0d-458c-ba4a-2c3baa7cd0e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_6f609fc5-df0d-458c-ba4a-2c3baa7cd0e4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LineOfCreditFacilityUnusedCapacityCommitmentFeeDecreasePercentage_8b0c4066-cfd5-4400-a19c-a1cabfcc1846" xlink:href="unit-20241231.xsd#unit_LineOfCreditFacilityUnusedCapacityCommitmentFeeDecreasePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_71c5e1ef-db51-471e-b443-e669bd8e377c" xlink:to="loc_unit_LineOfCreditFacilityUnusedCapacityCommitmentFeeDecreasePercentage_8b0c4066-cfd5-4400-a19c-a1cabfcc1846" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/NotesandOtherDebtTheNotesAssetBackedSecuritiesFacilityandDeferredFinancingCostNarrativeDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#NotesandOtherDebtTheNotesAssetBackedSecuritiesFacilityandDeferredFinancingCostNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/NotesandOtherDebtTheNotesAssetBackedSecuritiesFacilityandDeferredFinancingCostNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_097ca96b-6254-4422-a99f-74bba86671c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_DebtInstrumentAxis_097ca96b-6254-4422-a99f-74bba86671c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_097ca96b-6254-4422-a99f-74bba86671c3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_097ca96b-6254-4422-a99f-74bba86671c3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_097ca96b-6254-4422-a99f-74bba86671c3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_097ca96b-6254-4422-a99f-74bba86671c3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPointSevenFiveZeroPercentSeniorSecuredNotesDueTwoThousandTwentyEightMember_d59500f7-4fd0-4f42-b0f0-0e1c8773fc97" xlink:href="unit-20241231.xsd#unit_FourPointSevenFiveZeroPercentSeniorSecuredNotesDueTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_FourPointSevenFiveZeroPercentSeniorSecuredNotesDueTwoThousandTwentyEightMember_d59500f7-4fd0-4f42-b0f0-0e1c8773fc97" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_b5401b1c-06cf-4534-b8af-03794e463df7" xlink:href="unit-20241231.xsd#unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_FourPointSevenFivePercentageSeniorSecuredNotesDueAprilFifteenTwoThousandTwentyEightMember_b5401b1c-06cf-4534-b8af-03794e463df7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_c66f2d33-8757-4a23-b33d-e28f0038da60" xlink:href="unit-20241231.xsd#unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_c66f2d33-8757-4a23-b33d-e28f0038da60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SevenPointEightSevenFivePercentageSeniorSecuredNotesDueFebruaryFifteenTwoThousandTwentyFiveMember_63ba56ae-442c-4084-8fa2-fea0bff27211" xlink:href="unit-20241231.xsd#unit_SevenPointEightSevenFivePercentageSeniorSecuredNotesDueFebruaryFifteenTwoThousandTwentyFiveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_SevenPointEightSevenFivePercentageSeniorSecuredNotesDueFebruaryFifteenTwoThousandTwentyFiveMember_63ba56ae-442c-4084-8fa2-fea0bff27211" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointFiveZeroPercentageUnsecuredNotesDueFebruaryTwentyFourTwoThousandTwentyNineMember_f2a68c8a-d3e3-44b2-bc28-e19f74a78c4e" xlink:href="unit-20241231.xsd#unit_SixPointFiveZeroPercentageUnsecuredNotesDueFebruaryTwentyFourTwoThousandTwentyNineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_SixPointFiveZeroPercentageUnsecuredNotesDueFebruaryTwentyFourTwoThousandTwentyNineMember_f2a68c8a-d3e3-44b2-bc28-e19f74a78c4e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_e235abb7-91b4-4ab9-8425-91d8a676ee13" xlink:href="unit-20241231.xsd#unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_SixPointFiveZeroPercentageSeniorUnsecuredNotesDueFebruaryFifteenTwoThousandTwentyNineMember_e235abb7-91b4-4ab9-8425-91d8a676ee13" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SixPercentageSeniorUnsecuredNotesDueTwoThousandThirtyMember_51ca70df-cd9b-4324-a014-db84587138ff" xlink:href="unit-20241231.xsd#unit_SixPercentageSeniorUnsecuredNotesDueTwoThousandThirtyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_SixPercentageSeniorUnsecuredNotesDueTwoThousandThirtyMember_51ca70df-cd9b-4324-a014-db84587138ff" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FourPercentageExchangeableSeniorNotesDueJuneFifteenTwoThousandTwentyFourMember_b2e1df37-17a7-4af4-b262-41d8ac28f7aa" xlink:href="unit-20241231.xsd#unit_FourPercentageExchangeableSeniorNotesDueJuneFifteenTwoThousandTwentyFourMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_FourPercentageExchangeableSeniorNotesDueJuneFifteenTwoThousandTwentyFourMember_b2e1df37-17a7-4af4-b262-41d8ac28f7aa" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027Member_6e33c923-9144-4e44-893f-bc02691cd9fc" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ConvertibleSeniorNotes2027Member_6e33c923-9144-4e44-893f-bc02691cd9fc" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_30966ebf-9972-45b1-a5b5-6266ccf63215" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ConvertibleSeniorNotes2027ExcludingOverAllotmentOptionMember_30966ebf-9972-45b1-a5b5-6266ccf63215" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConvertibleSeniorNotes2027OverAllotmentOptionMember_793a0204-4b3e-4f3b-a12f-76d18d3c14ef" xlink:href="unit-20241231.xsd#unit_ConvertibleSeniorNotes2027OverAllotmentOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ConvertibleSeniorNotes2027OverAllotmentOptionMember_793a0204-4b3e-4f3b-a12f-76d18d3c14ef" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSCreditAgreementMember_9d2b7e82-8cae-4e5c-be4a-9b78a87fa0a3" xlink:href="unit-20241231.xsd#unit_ABSCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ABSCreditAgreementMember_9d2b7e82-8cae-4e5c-be4a-9b78a87fa0a3" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSLoanFacilityMember_134c475e-b7ef-4616-9225-292dfd12a256" xlink:href="unit-20241231.xsd#unit_ABSLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ABSLoanFacilityMember_134c475e-b7ef-4616-9225-292dfd12a256" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSNotesMember_bbc86c28-189f-4fdb-9b43-a37436dc0d54" xlink:href="unit-20241231.xsd#unit_ABSNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_f5314d99-f047-4122-b37d-172e4231f8dd" xlink:to="loc_unit_ABSNotesMember_bbc86c28-189f-4fdb-9b43-a37436dc0d54" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_Series20251ClassA2TermNotesMember_7291152f-b68a-4256-a083-b95f62820ccc" xlink:href="unit-20241231.xsd#unit_Series20251ClassA2TermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ABSNotesMember_bbc86c28-189f-4fdb-9b43-a37436dc0d54" xlink:to="loc_unit_Series20251ClassA2TermNotesMember_7291152f-b68a-4256-a083-b95f62820ccc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_Series20251ClassBTermNotesMember_624877b3-264b-4c6a-84ab-95725ce761f4" xlink:href="unit-20241231.xsd#unit_Series20251ClassBTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ABSNotesMember_bbc86c28-189f-4fdb-9b43-a37436dc0d54" xlink:to="loc_unit_Series20251ClassBTermNotesMember_624877b3-264b-4c6a-84ab-95725ce761f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_Series20251ClassCTermNotesMember_8324c66f-e94c-46ef-a004-9684f05747d3" xlink:href="unit-20241231.xsd#unit_Series20251ClassCTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_ABSNotesMember_bbc86c28-189f-4fdb-9b43-a37436dc0d54" xlink:to="loc_unit_Series20251ClassCTermNotesMember_8324c66f-e94c-46ef-a004-9684f05747d3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAxis_cc563fda-d855-4b2a-93a5-b042b37aac6f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_LineOfCreditFacilityAxis_cc563fda-d855-4b2a-93a5-b042b37aac6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_cc563fda-d855-4b2a-93a5-b042b37aac6f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_cc563fda-d855-4b2a-93a5-b042b37aac6f" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_cc563fda-d855-4b2a-93a5-b042b37aac6f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLenderDomain_e98be5c3-3e17-4911-aabf-43886094f912" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityLenderDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LineOfCreditFacilityAxis_cc563fda-d855-4b2a-93a5-b042b37aac6f" xlink:to="loc_us-gaap_LineOfCreditFacilityLenderDomain_e98be5c3-3e17-4911-aabf-43886094f912" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_BorrowersMember_47da4644-ac82-4a51-93ed-f9b864ada920" xlink:href="unit-20241231.xsd#unit_BorrowersMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLenderDomain_e98be5c3-3e17-4911-aabf-43886094f912" xlink:to="loc_unit_BorrowersMember_47da4644-ac82-4a51-93ed-f9b864ada920" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_a8a966fe-54ac-4d35-b7a6-59b6f40a137e" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_dei_LegalEntityAxis_a8a966fe-54ac-4d35-b7a6-59b6f40a137e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_a8a966fe-54ac-4d35-b7a6-59b6f40a137e_default" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_a8a966fe-54ac-4d35-b7a6-59b6f40a137e" xlink:to="loc_dei_EntityDomain_a8a966fe-54ac-4d35-b7a6-59b6f40a137e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_5fe3bcad-6c0d-4fb3-ae26-b88aae5c9f31" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_a8a966fe-54ac-4d35-b7a6-59b6f40a137e" xlink:to="loc_dei_EntityDomain_5fe3bcad-6c0d-4fb3-ae26-b88aae5c9f31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember_6adcc4c6-f279-45a8-ae8c-e3ca8fcf3be9" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_5fe3bcad-6c0d-4fb3-ae26-b88aae5c9f31" xlink:to="loc_unit_UnitiGroupLPUnitiGroupFinanceTwoThousandNineteenIncAndCSLCapitalLLCMember_6adcc4c6-f279-45a8-ae8c-e3ca8fcf3be9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e3c4c464-cbcc-4f97-9919-069ee2cb6c86" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_fa28b1b9-467e-4fbc-889e-aebd5c4c4c84" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e3c4c464-cbcc-4f97-9919-069ee2cb6c86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_2ec991ef-0921-4fdf-83b1-11a67354f360" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e3c4c464-cbcc-4f97-9919-069ee2cb6c86" xlink:to="loc_us-gaap_SecuredDebtMember_2ec991ef-0921-4fdf-83b1-11a67354f360" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtMember_bfdc7de5-30ac-4080-bebf-09f799442948" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConvertibleDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e3c4c464-cbcc-4f97-9919-069ee2cb6c86" xlink:to="loc_us-gaap_ConvertibleDebtMember_bfdc7de5-30ac-4080-bebf-09f799442948" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_6245381c-a364-4cd8-b9d2-733ebd1e0ead" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_e3c4c464-cbcc-4f97-9919-069ee2cb6c86" xlink:to="loc_us-gaap_LineOfCreditMember_6245381c-a364-4cd8-b9d2-733ebd1e0ead" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_22ac2030-9827-4c37-b421-e7965f14d0ac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_22ac2030-9827-4c37-b421-e7965f14d0ac" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_22ac2030-9827-4c37-b421-e7965f14d0ac_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_22ac2030-9827-4c37-b421-e7965f14d0ac" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_22ac2030-9827-4c37-b421-e7965f14d0ac_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_3fa6358e-567e-4462-acd5-31f8aa13ce01" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_22ac2030-9827-4c37-b421-e7965f14d0ac" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_3fa6358e-567e-4462-acd5-31f8aa13ce01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_32eccdf1-8665-4942-b75d-510ef997ee9c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_3fa6358e-567e-4462-acd5-31f8aa13ce01" xlink:to="loc_us-gaap_SubsequentEventMember_32eccdf1-8665-4942-b75d-510ef997ee9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_dd425677-6ec1-40b4-a0a5-63ca800340d1" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_srt_RangeAxis_dd425677-6ec1-40b4-a0a5-63ca800340d1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dd425677-6ec1-40b4-a0a5-63ca800340d1_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_dd425677-6ec1-40b4-a0a5-63ca800340d1" xlink:to="loc_srt_RangeMember_dd425677-6ec1-40b4-a0a5-63ca800340d1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_18ec25bf-6820-478c-ada2-8779f5bae791" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_dd425677-6ec1-40b4-a0a5-63ca800340d1" xlink:to="loc_srt_RangeMember_18ec25bf-6820-478c-ada2-8779f5bae791" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_35903af6-c6e5-46f4-8af9-19d6436e315d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_18ec25bf-6820-478c-ada2-8779f5bae791" xlink:to="loc_srt_MaximumMember_35903af6-c6e5-46f4-8af9-19d6436e315d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightAxis_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_ClassOfWarrantOrRightAxis_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightDomain_ff9c0407-479e-4c3d-a57b-0e59d87eafe7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ClassOfWarrantOrRightAxis_4c4a3932-f77e-4e85-b86d-fbcfd7ab0e4b" xlink:to="loc_us-gaap_ClassOfWarrantOrRightDomain_ff9c0407-479e-4c3d-a57b-0e59d87eafe7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CommonStockWarrantsMember_d7b30dd9-963e-4cd6-be30-3b2273aa8d71" xlink:href="unit-20241231.xsd#unit_CommonStockWarrantsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightDomain_ff9c0407-479e-4c3d-a57b-0e59d87eafe7" xlink:to="loc_unit_CommonStockWarrantsMember_d7b30dd9-963e-4cd6-be30-3b2273aa8d71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_0455f0dc-90fe-48ed-96e7-599aad9d7631" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_srt_CounterpartyNameAxis_0455f0dc-90fe-48ed-96e7-599aad9d7631" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0455f0dc-90fe-48ed-96e7-599aad9d7631_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_0455f0dc-90fe-48ed-96e7-599aad9d7631" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_0455f0dc-90fe-48ed-96e7-599aad9d7631_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_53ab3f0d-db63-4d07-820c-3036cc9b74c2" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_0455f0dc-90fe-48ed-96e7-599aad9d7631" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_53ab3f0d-db63-4d07-820c-3036cc9b74c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_Counterparties2019Member_df061d6e-e48d-4548-aa55-4a44c2bf9d39" xlink:href="unit-20241231.xsd#unit_Counterparties2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_53ab3f0d-db63-4d07-820c-3036cc9b74c2" xlink:to="loc_unit_Counterparties2019Member_df061d6e-e48d-4548-aa55-4a44c2bf9d39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_ce3993b2-e4d2-407e-b084-6facaaa6bcc2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_0306a682-93a0-40ff-85d7-6399f5b8ee0c" xlink:to="loc_us-gaap_CreditFacilityAxis_ce3993b2-e4d2-407e-b084-6facaaa6bcc2" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_ce3993b2-e4d2-407e-b084-6facaaa6bcc2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_ce3993b2-e4d2-407e-b084-6facaaa6bcc2" xlink:to="loc_us-gaap_CreditFacilityDomain_ce3993b2-e4d2-407e-b084-6facaaa6bcc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_d9be4e16-ab57-441a-8159-2101bcd6b000" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_ce3993b2-e4d2-407e-b084-6facaaa6bcc2" xlink:to="loc_us-gaap_CreditFacilityDomain_d9be4e16-ab57-441a-8159-2101bcd6b000" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_f133e42b-fabf-4954-ad18-4eb4c7210390" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_d9be4e16-ab57-441a-8159-2101bcd6b000" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_f133e42b-fabf-4954-ad18-4eb4c7210390" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_79ad874d-a066-4036-8e09-accad303ad8b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_79ad874d-a066-4036-8e09-accad303ad8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8501afa5-38fa-4acf-8d27-39d6b2b0d7af" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_8501afa5-38fa-4acf-8d27-39d6b2b0d7af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_c6ac914a-6f2c-4716-adfc-046d1219da71" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_c6ac914a-6f2c-4716-adfc-046d1219da71" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_f2fd3e75-15fe-48a9-a3f9-f74519c64aab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_f2fd3e75-15fe-48a9-a3f9-f74519c64aab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_c2023941-7d37-4c4b-a6f6-5b52ad09c2ad" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_c2023941-7d37-4c4b-a6f6-5b52ad09c2ad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_b3912e16-7658-4623-b332-e2315bc36c8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_InterestExpense_b3912e16-7658-4623-b332-e2315bc36c8f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_f95ee625-9e61-4bcf-ab4e-617b7bdb1542" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_f95ee625-9e61-4bcf-ab4e-617b7bdb1542" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_4d9e584e-78f5-402e-b010-e5daa1f9b3e8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_4d9e584e-78f5-402e-b010-e5daa1f9b3e8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightOutstanding_9cbaa62c-3055-459e-b1eb-cfc47dfcd8ef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightOutstanding_9cbaa62c-3055-459e-b1eb-cfc47dfcd8ef" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_fce7075a-7d58-4cda-bb66-7b6d8da3582a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1_fce7075a-7d58-4cda-bb66-7b6d8da3582a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_eb52e5c7-ea7b-4877-9006-c6649c0f4e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_eb52e5c7-ea7b-4877-9006-c6649c0f4e7d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtAmount_6125dc4f-3098-45b4-b0b2-3ba98d15ea18" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ExtinguishmentOfDebtAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ExtinguishmentOfDebtAmount_6125dc4f-3098-45b4-b0b2-3ba98d15ea18" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebt_0449292b-2042-455c-a2a5-09faabd88041" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RepaymentsOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebt_0449292b-2042-455c-a2a5-09faabd88041" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost_496dc714-251b-48b4-bbef-3172a387f750" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebtBeforeWriteOffOfDeferredDebtIssuanceCost_496dc714-251b-48b4-bbef-3172a387f750" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_2f61ce2b-7b26-437a-8f9d-4d499a8bb557" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_WriteOffOfDeferredDebtIssuanceCost_2f61ce2b-7b26-437a-8f9d-4d499a8bb557" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities_5b8ebd3e-55bd-47c6-a102-21992d02d272" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ProceedsFromDerivativeInstrumentFinancingActivities_5b8ebd3e-55bd-47c6-a102-21992d02d272" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_8e352d4d-4704-4113-94de-0c97625ba966" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_RepaymentsOfDebt_8e352d4d-4704-4113-94de-0c97625ba966" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DebtInstrumentExchangeRateOfEquityShares_0ddbd070-22b7-40de-8922-07167d6a0bcd" xlink:href="unit-20241231.xsd#unit_DebtInstrumentExchangeRateOfEquityShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_unit_DebtInstrumentExchangeRateOfEquityShares_0ddbd070-22b7-40de-8922-07167d6a0bcd" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_4e633252-21c8-472a-ae50-837d0843e98f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_4e633252-21c8-472a-ae50-837d0843e98f" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_f6e6423a-ea0a-46ac-9c3b-b301b7ec83fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebt_f6e6423a-ea0a-46ac-9c3b-b301b7ec83fb" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_6896d0ea-4e40-4f0e-be80-207864834e80" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromDebtNetOfIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_ProceedsFromDebtNetOfIssuanceCosts_6896d0ea-4e40-4f0e-be80-207864834e80" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForDerivativeInstrumentFinancingActivities_6c370d30-067b-4573-8c41-6f5e16fe3063" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsForDerivativeInstrumentFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_PaymentsForDerivativeInstrumentFinancingActivities_6c370d30-067b-4573-8c41-6f5e16fe3063" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeCapPrice_aa13a96e-1f34-4d64-ae9f-84960b3d6ddf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeCapPrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_DerivativeCapPrice_aa13a96e-1f34-4d64-ae9f-84960b3d6ddf" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PremiumOverTheLastReportedCommonStockSalesPricePercentage_93951b2a-0987-4df4-aebe-301ed3c62150" xlink:href="unit-20241231.xsd#unit_PremiumOverTheLastReportedCommonStockSalesPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_unit_PremiumOverTheLastReportedCommonStockSalesPricePercentage_93951b2a-0987-4df4-aebe-301ed3c62150" xlink:type="arc" order="23"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_066edf2c-add8-4cc4-9318-a2be563dceb3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SaleOfStockPricePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_066edf2c-add8-4cc4-9318-a2be563dceb3" xlink:type="arc" order="24"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebt_f597c356-dd62-4cf1-a03c-1540430d5274" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpenseDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_InterestExpenseDebt_f597c356-dd62-4cf1-a03c-1540430d5274" xlink:type="arc" order="25"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseDebtExcludingAmortization_2845c9a9-2b88-48bc-8322-2d10b8461b9d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpenseDebtExcludingAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_InterestExpenseDebtExcludingAmortization_2845c9a9-2b88-48bc-8322-2d10b8461b9d" xlink:type="arc" order="26"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_52f0181a-3d43-4ae2-b91f-32f55d6ef2fa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_52f0181a-3d43-4ae2-b91f-32f55d6ef2fa" xlink:type="arc" order="27"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_84c8575c-5037-4475-8dbe-7bcfd0193d9b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_51654df4-0e13-44f1-9f65-18a45576b90e" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_84c8575c-5037-4475-8dbe-7bcfd0193d9b" xlink:type="arc" order="28"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/StockBasedCompensationAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#StockBasedCompensationAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/StockBasedCompensationAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_32a30ee7-29ac-434a-b354-c6564718531c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_32a30ee7-29ac-434a-b354-c6564718531c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_d1a35cd0-f799-453e-b53c-2d762a1f530a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_32a30ee7-29ac-434a-b354-c6564718531c" xlink:to="loc_us-gaap_AwardTypeAxis_d1a35cd0-f799-453e-b53c-2d762a1f530a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d1a35cd0-f799-453e-b53c-2d762a1f530a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_d1a35cd0-f799-453e-b53c-2d762a1f530a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d1a35cd0-f799-453e-b53c-2d762a1f530a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9b3dbab-0146-4d12-9d33-cbde23653715" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_d1a35cd0-f799-453e-b53c-2d762a1f530a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9b3dbab-0146-4d12-9d33-cbde23653715" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_9e7fa121-9254-4b01-ae74-67493820b62a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9b3dbab-0146-4d12-9d33-cbde23653715" xlink:to="loc_us-gaap_RestrictedStockMember_9e7fa121-9254-4b01-ae74-67493820b62a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_bafb88a4-7f78-40b6-b905-d21046c94d46" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9b3dbab-0146-4d12-9d33-cbde23653715" xlink:to="loc_us-gaap_PerformanceSharesMember_bafb88a4-7f78-40b6-b905-d21046c94d46" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_9f2c1249-07db-4505-8778-2cfc427d3b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d9b3dbab-0146-4d12-9d33-cbde23653715" xlink:to="loc_us-gaap_EmployeeStockMember_9f2c1249-07db-4505-8778-2cfc427d3b3d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_32a30ee7-29ac-434a-b354-c6564718531c" xlink:to="loc_srt_RangeAxis_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23" xlink:to="loc_srt_RangeMember_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_795fdff2-5555-4c9b-8dd9-44ecc064f665" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_86b2d7ce-0df2-4eb7-ac3c-ae462c3a3d23" xlink:to="loc_srt_RangeMember_795fdff2-5555-4c9b-8dd9-44ecc064f665" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_19745beb-d063-4b9c-a3f9-e5537630405a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_795fdff2-5555-4c9b-8dd9-44ecc064f665" xlink:to="loc_srt_MinimumMember_19745beb-d063-4b9c-a3f9-e5537630405a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ec3848ee-87b7-402a-a711-59d115240a25" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_795fdff2-5555-4c9b-8dd9-44ecc064f665" xlink:to="loc_srt_MaximumMember_ec3848ee-87b7-402a-a711-59d115240a25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_2be97d3a-78cd-4689-b3ce-6fd3c731629c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_32a30ee7-29ac-434a-b354-c6564718531c" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_2be97d3a-78cd-4689-b3ce-6fd3c731629c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_2be97d3a-78cd-4689-b3ce-6fd3c731629c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_2be97d3a-78cd-4689-b3ce-6fd3c731629c" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_2be97d3a-78cd-4689-b3ce-6fd3c731629c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_c940d387-fd51-4f4d-8dd7-2a0f43a7d71c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_2be97d3a-78cd-4689-b3ce-6fd3c731629c" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_c940d387-fd51-4f4d-8dd7-2a0f43a7d71c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_d70943bb-4049-437d-a146-7eee3991e0b7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_c940d387-fd51-4f4d-8dd7-2a0f43a7d71c" xlink:to="loc_us-gaap_EmployeeSeveranceMember_d70943bb-4049-437d-a146-7eee3991e0b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a7e4351b-c2c5-4860-8bca-1ad006670c3c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a7e4351b-c2c5-4860-8bca-1ad006670c3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue_173c7daf-c71a-4936-8a6c-2e8f197a7f23" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue_173c7daf-c71a-4936-8a6c-2e8f197a7f23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_c3f1c02e-4020-45e2-be6c-beea0dc7ad90" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_c3f1c02e-4020-45e2-be6c-beea0dc7ad90" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_707c1f4c-9708-4b27-932e-6531876f7e2c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_707c1f4c-9708-4b27-932e-6531876f7e2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_90e4bc70-f3e2-48b4-9a53-14f2d65b55ed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_90e4bc70-f3e2-48b4-9a53-14f2d65b55ed" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_25c544e4-9788-46dc-b878-47b35be533ce" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_25c544e4-9788-46dc-b878-47b35be533ce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_2cef56cb-d802-422b-89cb-952f059136ed" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_2cef56cb-d802-422b-89cb-952f059136ed" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_9cfe9049-8b36-409a-9abf-cf62098b529a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_9cfe9049-8b36-409a-9abf-cf62098b529a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfTargetShares_36e290ca-49e3-451b-8a45-fdf611ea6040" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfTargetShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfTargetShares_36e290ca-49e3-451b-8a45-fdf611ea6040" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_cf023a11-3789-4b2f-ae50-0d19505f4b36" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_cf023a11-3789-4b2f-ae50-0d19505f4b36" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodPercentageOfTargetAmount_53a169e0-28c1-4240-b4bb-0613920c468b" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodPercentageOfTargetAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriodPercentageOfTargetAmount_53a169e0-28c1-4240-b4bb-0613920c468b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_004f0b13-0850-453f-88aa-368e595b4375" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_004f0b13-0850-453f-88aa-368e595b4375" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dd956f0c-3701-458b-ab12-50a2e6cfa3c3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_dd956f0c-3701-458b-ab12-50a2e6cfa3c3" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_35c65570-844c-474b-86aa-3a3d3a50300e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_35c65570-844c-474b-86aa-3a3d3a50300e" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_13007e02-2767-4c3b-a371-291630252f90" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_13007e02-2767-4c3b-a371-291630252f90" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualPurchasePlanPeriods_4a7fd26d-f20e-4bee-8f4e-72648fee6583" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualPurchasePlanPeriods"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualPurchasePlanPeriods_4a7fd26d-f20e-4bee-8f4e-72648fee6583" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod_59eba394-41b0-4e59-a52e-8233bf790a7e" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod_59eba394-41b0-4e59-a52e-8233bf790a7e" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_d960fdb8-a5e4-4f4a-9beb-d826faf83f76" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_d960fdb8-a5e4-4f4a-9beb-d826faf83f76" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionAmount_00b84164-62fd-42a9-9540-8e70a751c7d4" xlink:href="unit-20241231.xsd#unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_unit_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionAmount_00b84164-62fd-42a9-9540-8e70a751c7d4" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_b3a4938e-5a13-4c71-9240-c0fd4f58f1b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_b3a4938e-5a13-4c71-9240-c0fd4f58f1b0" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_49b6fbcc-5f37-410a-b333-16c04162788d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_49b6fbcc-5f37-410a-b333-16c04162788d" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_eebb0493-d3a2-41ae-8ebc-dfaa73d9b4ff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_942cab10-4251-48cc-a6af-12745f5e974c" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_eebb0493-d3a2-41ae-8ebc-dfaa73d9b4ff" xlink:type="arc" order="21"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/StockBasedCompensationScheduleofUnvestedRestrictedStockAwardsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#StockBasedCompensationScheduleofUnvestedRestrictedStockAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/StockBasedCompensationScheduleofUnvestedRestrictedStockAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcf2a98d-832f-4086-bd0a-904b50a47724" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcf2a98d-832f-4086-bd0a-904b50a47724" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_49366b67-9caa-4403-ae58-24b2c1d37bf8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcf2a98d-832f-4086-bd0a-904b50a47724" xlink:to="loc_us-gaap_AwardTypeAxis_49366b67-9caa-4403-ae58-24b2c1d37bf8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_49366b67-9caa-4403-ae58-24b2c1d37bf8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_49366b67-9caa-4403-ae58-24b2c1d37bf8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_49366b67-9caa-4403-ae58-24b2c1d37bf8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9f74e8e1-8d15-40b9-a633-b5032b0d664b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_49366b67-9caa-4403-ae58-24b2c1d37bf8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9f74e8e1-8d15-40b9-a633-b5032b0d664b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_9c89f4bf-6e65-4ab8-ab91-798d502d7322" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9f74e8e1-8d15-40b9-a633-b5032b0d664b" xlink:to="loc_us-gaap_RestrictedStockMember_9c89f4bf-6e65-4ab8-ab91-798d502d7322" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_aefc44c6-29d4-48da-a283-cd960a9f4b96" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_aefc44c6-29d4-48da-a283-cd960a9f4b96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_f03522bc-8384-4137-a998-ad8bd7bc13b9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_f03522bc-8384-4137-a998-ad8bd7bc13b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5815d411-4b7c-42c1-b5d0-a2dded510d8e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_5815d411-4b7c-42c1-b5d0-a2dded510d8e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_51928876-45da-46b1-8d19-78f1ab48833f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_88dd6673-5f6b-4aa0-a918-428d412a263e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_51928876-45da-46b1-8d19-78f1ab48833f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_2a97ed33-7c4a-4a94-848f-18a0b88504ce" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_fe58ccd0-6945-4058-bd02-98095338ed05" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_fe58ccd0-6945-4058-bd02-98095338ed05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6d637bef-1c2d-4702-aecf-d33943d425d3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6d637bef-1c2d-4702-aecf-d33943d425d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_17d8d297-a831-4e11-bc01-1bf15cede52b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_17d8d297-a831-4e11-bc01-1bf15cede52b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d9c38830-9563-49c4-9250-5df6160dc21a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_64d47e2b-1314-4459-bb73-ff81aab06e9a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d9c38830-9563-49c4-9250-5df6160dc21a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_61fa6e4f-b221-4dbf-ba1a-940eb19fb5de" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_54faf12d-e1bb-44ec-ab8d-c9c1b816ae60" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_54faf12d-e1bb-44ec-ab8d-c9c1b816ae60" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_996c5e44-b7e4-406d-88f0-79e983270cac" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_54faf12d-e1bb-44ec-ab8d-c9c1b816ae60" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_996c5e44-b7e4-406d-88f0-79e983270cac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_36794a42-4141-4a73-8361-5fdbe48b1156" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4690aa66-dac3-4338-8b0c-052d33db4790" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_36794a42-4141-4a73-8361-5fdbe48b1156" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/StockBasedCompensationScheduleofUnvestedPerformancebasedRestrictedStockUnitsAwardsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#StockBasedCompensationScheduleofUnvestedPerformancebasedRestrictedStockUnitsAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/StockBasedCompensationScheduleofUnvestedPerformancebasedRestrictedStockUnitsAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2bd282d2-c9da-4f14-b8e2-21c9a40d40a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2bd282d2-c9da-4f14-b8e2-21c9a40d40a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_96e3027f-0f22-4efd-ad00-60d29b8a5a21" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2bd282d2-c9da-4f14-b8e2-21c9a40d40a8" xlink:to="loc_us-gaap_AwardTypeAxis_96e3027f-0f22-4efd-ad00-60d29b8a5a21" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96e3027f-0f22-4efd-ad00-60d29b8a5a21_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_96e3027f-0f22-4efd-ad00-60d29b8a5a21" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_96e3027f-0f22-4efd-ad00-60d29b8a5a21_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c7ba39ae-a5fc-48f8-9315-0c8384f4f85e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_96e3027f-0f22-4efd-ad00-60d29b8a5a21" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c7ba39ae-a5fc-48f8-9315-0c8384f4f85e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_11a67f97-2960-4400-b11e-6cd46ea2d785" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_c7ba39ae-a5fc-48f8-9315-0c8384f4f85e" xlink:to="loc_us-gaap_PerformanceSharesMember_11a67f97-2960-4400-b11e-6cd46ea2d785" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_f3c86e03-c035-45bc-992a-cfca268b109b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_f3c86e03-c035-45bc-992a-cfca268b109b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_85009d2a-f2d7-4704-bc8b-40b743708250" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_85009d2a-f2d7-4704-bc8b-40b743708250" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_9ca957cf-9a2e-49bf-9884-eb9223bddd0d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_9ca957cf-9a2e-49bf-9884-eb9223bddd0d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4511e570-2e12-4b69-9c67-1ed591092bb8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedNumberOfSharesRollForward_60b11cb9-06e7-45f7-a1a3-afab2d71da6e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_4511e570-2e12-4b69-9c67-1ed591092bb8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_6cfddc32-dff5-41c2-bf64-7b4c2205cd50" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4863be88-de4d-4bfc-ba5b-490f6aff5d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_4863be88-de4d-4bfc-ba5b-490f6aff5d0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6873f109-21c7-43fa-aa38-6640104d55fb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_6873f109-21c7-43fa-aa38-6640104d55fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_897530b9-d640-47e7-b51d-11f7e88f0e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_897530b9-d640-47e7-b51d-11f7e88f0e5d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_b376e746-50d1-4a47-b0d5-f89bb9205aff" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_8f314d37-b41c-4342-aac1-f0c82a539bd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_b376e746-50d1-4a47-b0d5-f89bb9205aff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_1f78f7a2-307d-4d81-8a51-05f6a4769dcc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_f008eb03-ee00-4fc7-ae33-4b0b6faf3474" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_f008eb03-ee00-4fc7-ae33-4b0b6faf3474" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_d7d9fbdd-0545-41ba-9407-fb0769d2e108" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract_f008eb03-ee00-4fc7-ae33-4b0b6faf3474" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueNonvested_d7d9fbdd-0545-41ba-9407-fb0769d2e108" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_adf56b9e-d3b9-4a8e-8def-e1c03e0c2a77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e5782eb4-3b86-4ab4-843b-804eb0533496" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedIntrinsicValue_adf56b9e-d3b9-4a8e-8def-e1c03e0c2a77" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/StockBasedCompensationScheduleofAssumptionsusedtoValuePSUsGrantedDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#StockBasedCompensationScheduleofAssumptionsusedtoValuePSUsGrantedDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/StockBasedCompensationScheduleofAssumptionsusedtoValuePSUsGrantedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_eeaa9211-b255-40fe-a759-c83dc926bc3b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_eeaa9211-b255-40fe-a759-c83dc926bc3b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_1f06d806-2d67-41a6-baeb-0c3998f13586" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_eeaa9211-b255-40fe-a759-c83dc926bc3b" xlink:to="loc_us-gaap_AwardTypeAxis_1f06d806-2d67-41a6-baeb-0c3998f13586" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1f06d806-2d67-41a6-baeb-0c3998f13586_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_1f06d806-2d67-41a6-baeb-0c3998f13586" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_1f06d806-2d67-41a6-baeb-0c3998f13586_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dad6667f-687f-4242-b326-d183b71a16cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_1f06d806-2d67-41a6-baeb-0c3998f13586" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dad6667f-687f-4242-b326-d183b71a16cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_7835a3cd-a76c-415d-b301-c10b6e0d5b6f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_dad6667f-687f-4242-b326-d183b71a16cb" xlink:to="loc_us-gaap_PerformanceSharesMember_7835a3cd-a76c-415d-b301-c10b6e0d5b6f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_a0be2231-7c1a-45fb-a44f-f892388d26b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_a0be2231-7c1a-45fb-a44f-f892388d26b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_40510085-240e-4db1-9613-7b7f84f7e2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_40510085-240e-4db1-9613-7b7f84f7e2b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_e63a89d7-b035-4fca-8304-40a113731934" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_e63a89d7-b035-4fca-8304-40a113731934" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_12fb1e29-c354-41db-ba98-9fe4c17aa285" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_35116d06-5bbb-47da-bf91-72aa194963c4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_12fb1e29-c354-41db-ba98-9fe4c17aa285" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/StockBasedCompensationScheduleofAssumptionsusedtoValuePurchaseRightsGrantedUnderESPPDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#StockBasedCompensationScheduleofAssumptionsusedtoValuePurchaseRightsGrantedUnderESPPDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/StockBasedCompensationScheduleofAssumptionsusedtoValuePurchaseRightsGrantedUnderESPPDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3065ff90-a8da-461e-8e35-578d861cc343" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3065ff90-a8da-461e-8e35-578d861cc343" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_3326d8fc-7176-4d21-939f-134445fc0ccb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_3065ff90-a8da-461e-8e35-578d861cc343" xlink:to="loc_us-gaap_AwardTypeAxis_3326d8fc-7176-4d21-939f-134445fc0ccb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3326d8fc-7176-4d21-939f-134445fc0ccb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_3326d8fc-7176-4d21-939f-134445fc0ccb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_3326d8fc-7176-4d21-939f-134445fc0ccb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2720b667-320f-40df-ac0f-a9efeef86473" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_3326d8fc-7176-4d21-939f-134445fc0ccb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2720b667-320f-40df-ac0f-a9efeef86473" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_b0b024c6-bcde-4cd9-a461-838cdf8f0e58" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2720b667-320f-40df-ac0f-a9efeef86473" xlink:to="loc_us-gaap_EmployeeStockMember_b0b024c6-bcde-4cd9-a461-838cdf8f0e58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_da255d3e-192d-455a-a21e-d53c2c87ba7f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_da255d3e-192d-455a-a21e-d53c2c87ba7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_ddac5826-2ba3-4a60-ba77-eae3e0030f96" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_ddac5826-2ba3-4a60-ba77-eae3e0030f96" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_88da8b88-67fa-4df5-b4f2-ef23915d1d4b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_88da8b88-67fa-4df5-b4f2-ef23915d1d4b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_e7cfaa01-dfdb-4dfb-868b-a63a4f39471e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_4f838f5d-aec0-47af-8098-f8ef7f582342" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_e7cfaa01-dfdb-4dfb-868b-a63a4f39471e" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/EarningsPerShareAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#EarningsPerShareAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/EarningsPerShareAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_abf564a7-feee-406e-891e-91d716e106e3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_daf7d3fe-3d73-43c2-886d-5c8bb44c25a8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_abf564a7-feee-406e-891e-91d716e106e3" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_daf7d3fe-3d73-43c2-886d-5c8bb44c25a8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_709e5a8f-ed06-4703-a7f2-bc4cce91f922" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_daf7d3fe-3d73-43c2-886d-5c8bb44c25a8" xlink:to="loc_us-gaap_AwardTypeAxis_709e5a8f-ed06-4703-a7f2-bc4cce91f922" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_709e5a8f-ed06-4703-a7f2-bc4cce91f922_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_709e5a8f-ed06-4703-a7f2-bc4cce91f922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_709e5a8f-ed06-4703-a7f2-bc4cce91f922_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b7a43e1a-46fc-4c2b-99e4-13502c0026f0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_709e5a8f-ed06-4703-a7f2-bc4cce91f922" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b7a43e1a-46fc-4c2b-99e4-13502c0026f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_0497d7b9-9dd1-44c5-b094-8e9ca2f6bad0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b7a43e1a-46fc-4c2b-99e4-13502c0026f0" xlink:to="loc_us-gaap_PerformanceSharesMember_0497d7b9-9dd1-44c5-b094-8e9ca2f6bad0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_daf7d3fe-3d73-43c2-886d-5c8bb44c25a8" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_ce7fe896-8af8-45df-ab9b-0b935f59b401" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_9a30b866-e3ce-4cad-82d6-5f5dd6b64a90" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_ce7fe896-8af8-45df-ab9b-0b935f59b401" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConvertibleDebtSecuritiesMember_59231fea-c257-4366-b55c-f84cc33ad330" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConvertibleDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_ce7fe896-8af8-45df-ab9b-0b935f59b401" xlink:to="loc_us-gaap_ConvertibleDebtSecuritiesMember_59231fea-c257-4366-b55c-f84cc33ad330" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_7a011830-641e-491e-9e1e-898e661727b6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_abf564a7-feee-406e-891e-91d716e106e3" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_7a011830-641e-491e-9e1e-898e661727b6" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SegmentInformationScheduleofSegmentReportingInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SegmentInformationScheduleofSegmentReportingInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SegmentInformationScheduleofSegmentReportingInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3593613f-3cae-4537-8992-43db50970f1f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3593613f-3cae-4537-8992-43db50970f1f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_eedd9325-b672-4ea9-b831-3fb37fa3f334" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3593613f-3cae-4537-8992-43db50970f1f" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_eedd9325-b672-4ea9-b831-3fb37fa3f334" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_eedd9325-b672-4ea9-b831-3fb37fa3f334_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_eedd9325-b672-4ea9-b831-3fb37fa3f334" xlink:to="loc_us-gaap_SegmentDomain_eedd9325-b672-4ea9-b831-3fb37fa3f334_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_480053c6-ffc8-44db-a54c-c27f1aef57c5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_eedd9325-b672-4ea9-b831-3fb37fa3f334" xlink:to="loc_us-gaap_SegmentDomain_480053c6-ffc8-44db-a54c-c27f1aef57c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasingSegmentMember_5d09b783-046e-411e-ac9a-856164c82558" xlink:href="unit-20241231.xsd#unit_LeasingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_480053c6-ffc8-44db-a54c-c27f1aef57c5" xlink:to="loc_unit_LeasingSegmentMember_5d09b783-046e-411e-ac9a-856164c82558" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_02d94454-ed63-489a-b578-74fe83fc444e" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_480053c6-ffc8-44db-a54c-c27f1aef57c5" xlink:to="loc_unit_FiberSegmentMember_02d94454-ed63-489a-b578-74fe83fc444e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_2eb7b46d-e2b2-4125-a2f1-65d78f1de309" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_3593613f-3cae-4537-8992-43db50970f1f" xlink:to="loc_srt_ConsolidationItemsAxis_2eb7b46d-e2b2-4125-a2f1-65d78f1de309" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_2eb7b46d-e2b2-4125-a2f1-65d78f1de309_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_2eb7b46d-e2b2-4125-a2f1-65d78f1de309" xlink:to="loc_srt_ConsolidationItemsDomain_2eb7b46d-e2b2-4125-a2f1-65d78f1de309_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_1eb62298-4519-46d6-8f48-5963ef321903" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_2eb7b46d-e2b2-4125-a2f1-65d78f1de309" xlink:to="loc_srt_ConsolidationItemsDomain_1eb62298-4519-46d6-8f48-5963ef321903" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_4e42fc6c-0b1b-487c-b795-097be5004dea" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_1eb62298-4519-46d6-8f48-5963ef321903" xlink:to="loc_us-gaap_OperatingSegmentsMember_4e42fc6c-0b1b-487c-b795-097be5004dea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_9bd5d974-3467-4d28-9e7d-be2aaa40d9b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_1eb62298-4519-46d6-8f48-5963ef321903" xlink:to="loc_us-gaap_CorporateNonSegmentMember_9bd5d974-3467-4d28-9e7d-be2aaa40d9b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_dea5023f-3f65-4bfa-92a3-50dcd2f85c56" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_us-gaap_Revenues_dea5023f-3f65-4bfa-92a3-50dcd2f85c56" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization_8fe2375a-fd47-49f7-b28f-55f499afc489" xlink:href="unit-20241231.xsd#unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization_8fe2375a-fd47-49f7-b28f-55f499afc489" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_5b66e9b5-8341-4536-b303-0602f43eca32" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_InterestExpense_5b66e9b5-8341-4536-b303-0602f43eca32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_7f9b1720-d322-4f9a-aad9-c334a224178f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_DepreciationAndAmortization_7f9b1720-d322-4f9a-aad9-c334a224178f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SegmentReportingInformationOtherIncomeExpenseNet_06f6c389-35a4-4b84-8f18-b3f7c6be2fcd" xlink:href="unit-20241231.xsd#unit_SegmentReportingInformationOtherIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_unit_SegmentReportingInformationOtherIncomeExpenseNet_06f6c389-35a4-4b84-8f18-b3f7c6be2fcd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TransactionRelatedAndOtherCosts_da8f6b23-909c-4921-aa9a-33442fa4be23" xlink:href="unit-20241231.xsd#unit_TransactionRelatedAndOtherCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_unit_TransactionRelatedAndOtherCosts_da8f6b23-909c-4921-aa9a-33442fa4be23" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_9b87f591-ca8d-447f-bf73-ca7f4e764015" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_9b87f591-ca8d-447f-bf73-ca7f4e764015" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_2e19d01a-fb09-4c9e-ad39-1820b8115acc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnSalesOfInvestmentRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_2e19d01a-fb09-4c9e-ad39-1820b8115acc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_ac2a453b-f24f-45b7-a07b-71e800d868f3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_ac2a453b-f24f-45b7-a07b-71e800d868f3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_27b9b014-377c-4a8c-b198-636f61c4af66" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_ShareBasedCompensation_27b9b014-377c-4a8c-b198-636f61c4af66" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_3e9f6d41-07af-4378-a0dc-680195789427" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_3e9f6d41-07af-4378-a0dc-680195789427" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustmentsForEquityInEarningsFromUnconsolidatedEntities_b6d57b4d-1f57-4ead-9ddf-f57c065347b1" xlink:href="unit-20241231.xsd#unit_AdjustmentsForEquityInEarningsFromUnconsolidatedEntities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReconciliationFromSegmentTotalsToConsolidatedAbstract_204b1eb0-9fd7-4807-82c2-0248c00a647b" xlink:to="loc_unit_AdjustmentsForEquityInEarningsFromUnconsolidatedEntities_b6d57b4d-1f57-4ead-9ddf-f57c065347b1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_e0e78daa-9a81-4d4e-a30b-394784cf2c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_us-gaap_ProfitLoss_e0e78daa-9a81-4d4e-a30b-394784cf2c0b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_6309aaf4-8749-4438-8621-30bc92c2f45a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_31ede80e-cfbc-4670-aa39-7c1f97b9cfdc" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_6309aaf4-8749-4438-8621-30bc92c2f45a" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SegmentInformationScheduleofOperatingSegmentReportingInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SegmentInformationScheduleofOperatingSegmentReportingInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SegmentInformationScheduleofOperatingSegmentReportingInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_540d6408-1411-4b7b-9daa-0b9f6f9c4c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_540d6408-1411-4b7b-9daa-0b9f6f9c4c5a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_ce03d328-7376-487b-b460-ab4e7b7f2bd0" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_540d6408-1411-4b7b-9daa-0b9f6f9c4c5a" xlink:to="loc_srt_ConsolidationItemsAxis_ce03d328-7376-487b-b460-ab4e7b7f2bd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_ce03d328-7376-487b-b460-ab4e7b7f2bd0_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_ce03d328-7376-487b-b460-ab4e7b7f2bd0" xlink:to="loc_srt_ConsolidationItemsDomain_ce03d328-7376-487b-b460-ab4e7b7f2bd0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_68443e66-dfd5-4657-b5b4-9089398d5e3e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_ce03d328-7376-487b-b460-ab4e7b7f2bd0" xlink:to="loc_srt_ConsolidationItemsDomain_68443e66-dfd5-4657-b5b4-9089398d5e3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_52ed45b6-5079-410d-a4f8-f0fcdbf28b5d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_68443e66-dfd5-4657-b5b4-9089398d5e3e" xlink:to="loc_us-gaap_OperatingSegmentsMember_52ed45b6-5079-410d-a4f8-f0fcdbf28b5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_7f237b77-70f7-41cb-9ef7-cec4434c325e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_540d6408-1411-4b7b-9daa-0b9f6f9c4c5a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_7f237b77-70f7-41cb-9ef7-cec4434c325e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7f237b77-70f7-41cb-9ef7-cec4434c325e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7f237b77-70f7-41cb-9ef7-cec4434c325e" xlink:to="loc_us-gaap_SegmentDomain_7f237b77-70f7-41cb-9ef7-cec4434c325e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_52b7b3e6-ae78-482b-ad84-ee17b7f72946" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_7f237b77-70f7-41cb-9ef7-cec4434c325e" xlink:to="loc_us-gaap_SegmentDomain_52b7b3e6-ae78-482b-ad84-ee17b7f72946" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_88e7b3f3-dca4-43cf-bb9a-12347ac5714f" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_52b7b3e6-ae78-482b-ad84-ee17b7f72946" xlink:to="loc_unit_FiberSegmentMember_88e7b3f3-dca4-43cf-bb9a-12347ac5714f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasingSegmentMember_b03e2a83-e378-47fe-bc15-906fe1f6de63" xlink:href="unit-20241231.xsd#unit_LeasingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_52b7b3e6-ae78-482b-ad84-ee17b7f72946" xlink:to="loc_unit_LeasingSegmentMember_b03e2a83-e378-47fe-bc15-906fe1f6de63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_fabc7ef1-6a75-4e11-8df7-5b3de38e951f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_us-gaap_Revenues_fabc7ef1-6a75-4e11-8df7-5b3de38e951f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_EmployeeRelatedExcludingStockBasedCompensationAbstract_0b68ad8f-c66a-4ea7-93c1-a13d4f4ce3c7" xlink:href="unit-20241231.xsd#unit_EmployeeRelatedExcludingStockBasedCompensationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_unit_EmployeeRelatedExcludingStockBasedCompensationAbstract_0b68ad8f-c66a-4ea7-93c1-a13d4f4ce3c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_f1adbe7c-9116-4524-9fbc-c5204653f38b" xlink:href="unit-20241231.xsd#unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_EmployeeRelatedExcludingStockBasedCompensationAbstract_0b68ad8f-c66a-4ea7-93c1-a13d4f4ce3c7" xlink:to="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_f1adbe7c-9116-4524-9fbc-c5204653f38b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_4f2466f1-343f-41e4-ac65-415a1ae35793" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_EmployeeRelatedExcludingStockBasedCompensationAbstract_0b68ad8f-c66a-4ea7-93c1-a13d4f4ce3c7" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_4f2466f1-343f-41e4-ac65-415a1ae35793" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_Network_d76e4a7a-fdbe-481d-b8ed-e19b9dac42c5" xlink:href="unit-20241231.xsd#unit_Network"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_unit_Network_d76e4a7a-fdbe-481d-b8ed-e19b9dac42c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_InstallationEquipmentAndOtherNonRecurringCharges_ebfca1d5-fbec-4622-afe9-3dccffb287ba" xlink:href="unit-20241231.xsd#unit_InstallationEquipmentAndOtherNonRecurringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_unit_InstallationEquipmentAndOtherNonRecurringCharges_ebfca1d5-fbec-4622-afe9-3dccffb287ba" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InsuranceCommissions_42ca8633-ed4d-4ac8-855b-879714197e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InsuranceCommissions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_us-gaap_InsuranceCommissions_42ca8633-ed4d-4ac8-855b-879714197e7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfessionalFees_40701856-c19f-4201-bf70-8265fa6c9d8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfessionalFees"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_us-gaap_ProfessionalFees_40701856-c19f-4201-bf70-8265fa6c9d8f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherExpenses_8ae207a2-234b-4acb-8da2-6cefe68e3dcc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_us-gaap_OtherExpenses_8ae207a2-234b-4acb-8da2-6cefe68e3dcc" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization_50bba9df-032a-41df-9bb9-244e75dba804" xlink:href="unit-20241231.xsd#unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_1e04704a-983a-4c21-a195-cfd007bf02e5" xlink:to="loc_unit_AdjustedEarningsBeforeInterestTaxesDepreciationAndAmortization_50bba9df-032a-41df-9bb9-244e75dba804" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SegmentInformationScheduleofTotalAssetsbyBusinessSegmentDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SegmentInformationScheduleofTotalAssetsbyBusinessSegmentDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SegmentInformationScheduleofTotalAssetsbyBusinessSegmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_78e8ddc1-e4f8-4511-91fb-232a85792b88" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0335c0a0-7d83-4587-b4a6-1b7514e41078" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_78e8ddc1-e4f8-4511-91fb-232a85792b88" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0335c0a0-7d83-4587-b4a6-1b7514e41078" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0335c0a0-7d83-4587-b4a6-1b7514e41078" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804" xlink:to="loc_us-gaap_SegmentDomain_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a538a3f9-7230-4787-a355-f81ffa1b8f43" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_29a0e1ac-32bb-46d9-aa7c-73d9b8ef9804" xlink:to="loc_us-gaap_SegmentDomain_a538a3f9-7230-4787-a355-f81ffa1b8f43" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_LeasingSegmentMember_2e15f0ad-cf30-400d-bb8e-ced3cc574ebe" xlink:href="unit-20241231.xsd#unit_LeasingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a538a3f9-7230-4787-a355-f81ffa1b8f43" xlink:to="loc_unit_LeasingSegmentMember_2e15f0ad-cf30-400d-bb8e-ced3cc574ebe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberSegmentMember_bf126cb6-d2a6-4286-87f6-36d1d3d34c38" xlink:href="unit-20241231.xsd#unit_FiberSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a538a3f9-7230-4787-a355-f81ffa1b8f43" xlink:to="loc_unit_FiberSegmentMember_bf126cb6-d2a6-4286-87f6-36d1d3d34c38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0335c0a0-7d83-4587-b4a6-1b7514e41078" xlink:to="loc_srt_ConsolidationItemsAxis_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355" xlink:to="loc_srt_ConsolidationItemsDomain_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_609899c1-fb0d-42d8-94e7-cbff53d40731" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_8fa6ca46-68ab-47ba-b2c5-ee7ce140d355" xlink:to="loc_srt_ConsolidationItemsDomain_609899c1-fb0d-42d8-94e7-cbff53d40731" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_8ad1d4c3-454a-4adc-8786-3766127370f9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_609899c1-fb0d-42d8-94e7-cbff53d40731" xlink:to="loc_us-gaap_OperatingSegmentsMember_8ad1d4c3-454a-4adc-8786-3766127370f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_cac18211-2e13-4512-b800-68245ed809b7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_609899c1-fb0d-42d8-94e7-cbff53d40731" xlink:to="loc_us-gaap_CorporateNonSegmentMember_cac18211-2e13-4512-b800-68245ed809b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_e43b58c5-7bcc-4b72-8f3a-43d512fe2298" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_78e8ddc1-e4f8-4511-91fb-232a85792b88" xlink:to="loc_us-gaap_Assets_e43b58c5-7bcc-4b72-8f3a-43d512fe2298" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/AccumulatedOtherComprehensiveLossNarrativeDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#AccumulatedOtherComprehensiveLossNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/AccumulatedOtherComprehensiveLossNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_65be9980-5da2-4459-aa88-6f9eb32b52f3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2edb949a-22c5-4171-af29-3a82fb224669" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_65be9980-5da2-4459-aa88-6f9eb32b52f3" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2edb949a-22c5-4171-af29-3a82fb224669" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2edb949a-22c5-4171-af29-3a82fb224669" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_c40c54c6-7144-48aa-9642-2f0f06451873" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_41a7a972-61ad-48d5-92aa-25f5e6bb0fcb" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_c40c54c6-7144-48aa-9642-2f0f06451873" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_f3f402a0-5ab5-4479-9358-c6106510f0d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_c40c54c6-7144-48aa-9642-2f0f06451873" xlink:to="loc_us-gaap_InterestRateCapMember_f3f402a0-5ab5-4479-9358-c6106510f0d9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_70d00d56-2b5b-4e1f-b3e4-020749e54ec5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_2edb949a-22c5-4171-af29-3a82fb224669" xlink:to="loc_us-gaap_HedgingDesignationAxis_70d00d56-2b5b-4e1f-b3e4-020749e54ec5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_70d00d56-2b5b-4e1f-b3e4-020749e54ec5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_70d00d56-2b5b-4e1f-b3e4-020749e54ec5" xlink:to="loc_us-gaap_HedgingDesignationDomain_70d00d56-2b5b-4e1f-b3e4-020749e54ec5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_75549fdc-4fc9-45f9-a9d5-fce73fe7e112" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_70d00d56-2b5b-4e1f-b3e4-020749e54ec5" xlink:to="loc_us-gaap_HedgingDesignationDomain_75549fdc-4fc9-45f9-a9d5-fce73fe7e112" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3d49028b-ad1b-4862-b9b3-16a7be1ac083" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_75549fdc-4fc9-45f9-a9d5-fce73fe7e112" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_3d49028b-ad1b-4862-b9b3-16a7be1ac083" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_fcf871d0-5e3a-4efb-83f2-0e59c3b6181d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_65be9980-5da2-4459-aa88-6f9eb32b52f3" xlink:to="loc_us-gaap_DerivativeNotionalAmount_fcf871d0-5e3a-4efb-83f2-0e59c3b6181d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeCapInterestRate_4566f699-1146-46e8-92d4-896ab7226856" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeCapInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_65be9980-5da2-4459-aa88-6f9eb32b52f3" xlink:to="loc_us-gaap_DerivativeCapInterestRate_4566f699-1146-46e8-92d4-896ab7226856" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/AccumulatedOtherComprehensiveLossScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#AccumulatedOtherComprehensiveLossScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/AccumulatedOtherComprehensiveLossScheduleofChangesinAccumulatedOtherComprehensiveIncomeLossbyComponentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_24f4900f-b315-45c9-af3f-53586f28de1b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec60ed78-4358-4193-b67e-fd3b14a4a5f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_24f4900f-b315-45c9-af3f-53586f28de1b" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec60ed78-4358-4193-b67e-fd3b14a4a5f1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec60ed78-4358-4193-b67e-fd3b14a4a5f1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8" xlink:to="loc_us-gaap_EquityComponentDomain_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_0c8a0bf5-9abe-4fb4-ac4e-570aee3a73b3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cf362eb4-9cd9-42e5-ba1a-3b22dd1adff8" xlink:to="loc_us-gaap_EquityComponentDomain_0c8a0bf5-9abe-4fb4-ac4e-570aee3a73b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_42340b7f-e9bd-4cb3-aed9-f6f55e3fcb8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0c8a0bf5-9abe-4fb4-ac4e-570aee3a73b3" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_42340b7f-e9bd-4cb3-aed9-f6f55e3fcb8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AociAttributableToNoncontrollingInterestMember_45846658-2b01-4e73-8592-a08e554f38d4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AociAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0c8a0bf5-9abe-4fb4-ac4e-570aee3a73b3" xlink:to="loc_us-gaap_AociAttributableToNoncontrollingInterestMember_45846658-2b01-4e73-8592-a08e554f38d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_121c1a92-1b2e-4c8b-9eea-a2fae38badec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_0c8a0bf5-9abe-4fb4-ac4e-570aee3a73b3" xlink:to="loc_us-gaap_AociIncludingPortionAttributableToNoncontrollingInterestMember_121c1a92-1b2e-4c8b-9eea-a2fae38badec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_adaf8784-d5d1-456e-8996-80664d96753e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_ec60ed78-4358-4193-b67e-fd3b14a4a5f1" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_adaf8784-d5d1-456e-8996-80664d96753e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_adaf8784-d5d1-456e-8996-80664d96753e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_adaf8784-d5d1-456e-8996-80664d96753e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_adaf8784-d5d1-456e-8996-80664d96753e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_13bfc6be-897e-46b6-91db-cb6e1fbc7ddc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_adaf8784-d5d1-456e-8996-80664d96753e" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_13bfc6be-897e-46b6-91db-cb6e1fbc7ddc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NonTerminatedDerivativesMember_5893c2fa-7d97-43b3-9531-1e8479827e6d" xlink:href="unit-20241231.xsd#unit_NonTerminatedDerivativesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_13bfc6be-897e-46b6-91db-cb6e1fbc7ddc" xlink:to="loc_unit_NonTerminatedDerivativesMember_5893c2fa-7d97-43b3-9531-1e8479827e6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TerminatedInterestRateSwapMember_666bedbe-ef67-470f-a729-2a9bf1f8fd54" xlink:href="unit-20241231.xsd#unit_TerminatedInterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_13bfc6be-897e-46b6-91db-cb6e1fbc7ddc" xlink:to="loc_unit_TerminatedInterestRateSwapMember_666bedbe-ef67-470f-a729-2a9bf1f8fd54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_24f4900f-b315-45c9-af3f-53586f28de1b" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_4373ea27-b6f2-47a8-89a7-6b3ec1b73091" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_4373ea27-b6f2-47a8-89a7-6b3ec1b73091" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_93845e73-61cf-4bd3-9908-9c04d46b90a7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_93845e73-61cf-4bd3-9908-9c04d46b90a7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_7acf2a1b-aed3-4949-a368-e7d7c66ed4d5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_7acf2a1b-aed3-4949-a368-e7d7c66ed4d5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_63deba08-a009-41b0-afb5-279debdaa1c0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_cbfb6a86-c953-4e53-9f31-f50597ab06a1" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_63deba08-a009-41b0-afb5-279debdaa1c0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_c4845478-cc53-4b86-b2d6-5ab9f4067620" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/IncomeTaxesAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#IncomeTaxesAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/IncomeTaxesAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:href="unit-20241231.xsd#unit_IncomeTaxesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_IncomeTaxesTable_8dcfe2b0-3771-44f2-b22c-4fbc7f2cfe3b" xlink:href="unit-20241231.xsd#unit_IncomeTaxesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_unit_IncomeTaxesTable_8dcfe2b0-3771-44f2-b22c-4fbc7f2cfe3b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodAxis_0e5026f9-901a-4d73-ac36-0cf8bad8ac54" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TaxPeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_IncomeTaxesTable_8dcfe2b0-3771-44f2-b22c-4fbc7f2cfe3b" xlink:to="loc_us-gaap_TaxPeriodAxis_0e5026f9-901a-4d73-ac36-0cf8bad8ac54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_0e5026f9-901a-4d73-ac36-0cf8bad8ac54_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_0e5026f9-901a-4d73-ac36-0cf8bad8ac54" xlink:to="loc_us-gaap_TaxPeriodDomain_0e5026f9-901a-4d73-ac36-0cf8bad8ac54_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxPeriodDomain_e829484c-1e3f-4398-8fb3-e9a0f70a02a5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_TaxPeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_0e5026f9-901a-4d73-ac36-0cf8bad8ac54" xlink:to="loc_us-gaap_TaxPeriodDomain_e829484c-1e3f-4398-8fb3-e9a0f70a02a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TaxWithoutExpirePeriodMember_84681e81-c780-4663-88b6-b4c96ef4b66d" xlink:href="unit-20241231.xsd#unit_TaxWithoutExpirePeriodMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_e829484c-1e3f-4398-8fb3-e9a0f70a02a5" xlink:to="loc_unit_TaxWithoutExpirePeriodMember_84681e81-c780-4663-88b6-b4c96ef4b66d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_29151769-b383-4f33-bd33-b36f6d4a9382" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unit_IncomeTaxesTable_8dcfe2b0-3771-44f2-b22c-4fbc7f2cfe3b" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_29151769-b383-4f33-bd33-b36f6d4a9382" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_29151769-b383-4f33-bd33-b36f6d4a9382_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_29151769-b383-4f33-bd33-b36f6d4a9382" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_29151769-b383-4f33-bd33-b36f6d4a9382_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c991e942-91ee-463b-b870-9a6f916a42c1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_29151769-b383-4f33-bd33-b36f6d4a9382" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c991e942-91ee-463b-b870-9a6f916a42c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TowerCloudIncMember_82aafd93-6cf0-4ec6-9064-1d9e7fb5488b" xlink:href="unit-20241231.xsd#unit_TowerCloudIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_c991e942-91ee-463b-b870-9a6f916a42c1" xlink:to="loc_unit_TowerCloudIncMember_82aafd93-6cf0-4ec6-9064-1d9e7fb5488b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsValuationAllowance_904a51fc-b74d-4fce-be7c-f398f02662b3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredTaxAssetsValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_us-gaap_DeferredTaxAssetsValuationAllowance_904a51fc-b74d-4fce-be7c-f398f02662b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_a3bbc405-01ad-4c48-9507-913d8c44f539" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_us-gaap_OperatingLossCarryforwards_a3bbc405-01ad-4c48-9507-913d8c44f539" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_2c813c35-202e-48c1-9a97-59278d375f45" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_2c813c35-202e-48c1-9a97-59278d375f45" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense_2dda6aac-5ed6-4de4-ad15-5d0377ad9571" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense_2dda6aac-5ed6-4de4-ad15-5d0377ad9571" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_cf02b9d2-c50a-4e0f-8091-12a4a41290b0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unit_IncomeTaxesLineItems_8e769de4-c252-4d0c-947d-83d1ec0783e1" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued_cf02b9d2-c50a-4e0f-8091-12a4a41290b0" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/CapitalStockDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#CapitalStockDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/CapitalStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfCapitalizationEquityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCapitalizationEquityTable_0b36a257-1e57-400d-ada5-02eb1592d860" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ScheduleOfCapitalizationEquityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_ScheduleOfCapitalizationEquityTable_0b36a257-1e57-400d-ada5-02eb1592d860" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_b58e5bee-6818-4612-9005-dda80d71ada9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConversionOfStockByUniqueDescriptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityTable_0b36a257-1e57-400d-ada5-02eb1592d860" xlink:to="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_b58e5bee-6818-4612-9005-dda80d71ada9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_b58e5bee-6818-4612-9005-dda80d71ada9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_b58e5bee-6818-4612-9005-dda80d71ada9" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_b58e5bee-6818-4612-9005-dda80d71ada9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockNameDomain_15a3adaa-74e1-4df9-93fa-d1a0ef44caa8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConversionOfStockNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConversionOfStockByUniqueDescriptionAxis_b58e5bee-6818-4612-9005-dda80d71ada9" xlink:to="loc_us-gaap_ConversionOfStockNameDomain_15a3adaa-74e1-4df9-93fa-d1a0ef44caa8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CommonShareExchangeMember_bd19779d-a565-41b4-9ed8-c22806c27305" xlink:href="unit-20241231.xsd#unit_CommonShareExchangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_15a3adaa-74e1-4df9-93fa-d1a0ef44caa8" xlink:to="loc_unit_CommonShareExchangeMember_bd19779d-a565-41b4-9ed8-c22806c27305" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CashShareExchangeMember_54767028-c737-4c3c-b8fb-ab822707754c" xlink:href="unit-20241231.xsd#unit_CashShareExchangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_15a3adaa-74e1-4df9-93fa-d1a0ef44caa8" xlink:to="loc_unit_CashShareExchangeMember_54767028-c737-4c3c-b8fb-ab822707754c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CashSharePurchaseMember_3b85db94-76a6-49a8-9a31-e3ae62ea4f98" xlink:href="unit-20241231.xsd#unit_CashSharePurchaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConversionOfStockNameDomain_15a3adaa-74e1-4df9-93fa-d1a0ef44caa8" xlink:to="loc_unit_CashSharePurchaseMember_3b85db94-76a6-49a8-9a31-e3ae62ea4f98" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_a9c1145f-ed2c-4d4d-900e-067b5b377c08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityTable_0b36a257-1e57-400d-ada5-02eb1592d860" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_a9c1145f-ed2c-4d4d-900e-067b5b377c08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a9c1145f-ed2c-4d4d-900e-067b5b377c08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a9c1145f-ed2c-4d4d-900e-067b5b377c08" xlink:to="loc_us-gaap_EquityComponentDomain_a9c1145f-ed2c-4d4d-900e-067b5b377c08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_a5064e50-076e-4f06-b463-61ae990f8677" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_a9c1145f-ed2c-4d4d-900e-067b5b377c08" xlink:to="loc_us-gaap_EquityComponentDomain_a5064e50-076e-4f06-b463-61ae990f8677" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_74625fcd-64f0-4170-abc8-31efb9a94351" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_a5064e50-076e-4f06-b463-61ae990f8677" xlink:to="loc_us-gaap_NoncontrollingInterestMember_74625fcd-64f0-4170-abc8-31efb9a94351" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConversionOfStockRatio_b0843f17-8a2f-4fb7-b21e-c8579af0e757" xlink:href="unit-20241231.xsd#unit_ConversionOfStockRatio"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_unit_ConversionOfStockRatio_b0843f17-8a2f-4fb7-b21e-c8579af0e757" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockSharesConverted1_cab50076-705a-4fb7-b67e-a21197309f29" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConversionOfStockSharesConverted1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_ConversionOfStockSharesConverted1_cab50076-705a-4fb7-b67e-a21197309f29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConversionOfStockAmountConverted1_9a62db4d-2d50-4b61-b3b2-523b8b1ca49a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConversionOfStockAmountConverted1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_ConversionOfStockAmountConverted1_9a62db4d-2d50-4b61-b3b2-523b8b1ca49a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PercentageOfUnitsExchangedHeldByThirdParties_2164eb50-ab23-4cf3-99a1-cefed290e7ee" xlink:href="unit-20241231.xsd#unit_PercentageOfUnitsExchangedHeldByThirdParties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_unit_PercentageOfUnitsExchangedHeldByThirdParties_2164eb50-ab23-4cf3-99a1-cefed290e7ee" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_87750a08-e176-4e0c-bce0-4c4a073a2fb4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_87750a08-e176-4e0c-bce0-4c4a073a2fb4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_27bc1de1-10fd-465d-93c6-fc1697ec4cce" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_27bc1de1-10fd-465d-93c6-fc1697ec4cce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_c35b76be-10b6-4b48-b63c-b7f5f4b20e00" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_c35b76be-10b6-4b48-b63c-b7f5f4b20e00" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_fea13f7b-f8c8-4180-96be-e5e7eb70bf34" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_fea13f7b-f8c8-4180-96be-e5e7eb70bf34" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_8e33412c-0a60-4f1f-b4cc-e624824d78b4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfCapitalizationEquityLineItems_805dec0e-5e1e-408a-ad16-85a93134ec41" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_8e33412c-0a60-4f1f-b4cc-e624824d78b4" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/DividendsDistributionsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#DividendsDistributionsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/DividendsDistributionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableLineItems_48aae1b1-61b5-43a3-8fc1-82e741d566df" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableTable_e73aad41-d326-48a3-9355-06965a91e0b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DividendsPayableLineItems_48aae1b1-61b5-43a3-8fc1-82e741d566df" xlink:to="loc_us-gaap_DividendsPayableTable_e73aad41-d326-48a3-9355-06965a91e0b2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsAxis_16a05d6f-9f3a-4e35-9b28-2662022fe789" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DividendsPayableTable_e73aad41-d326-48a3-9355-06965a91e0b2" xlink:to="loc_us-gaap_DividendsAxis_16a05d6f-9f3a-4e35-9b28-2662022fe789" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsDomain_16a05d6f-9f3a-4e35-9b28-2662022fe789_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DividendsAxis_16a05d6f-9f3a-4e35-9b28-2662022fe789" xlink:to="loc_us-gaap_DividendsDomain_16a05d6f-9f3a-4e35-9b28-2662022fe789_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DividendsAxis_16a05d6f-9f3a-4e35-9b28-2662022fe789" xlink:to="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_O2024ADividendsMember_5bfe23a8-6e25-4da4-b620-fd8d735cfac0" xlink:href="unit-20241231.xsd#unit_O2024ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_O2024ADividendsMember_5bfe23a8-6e25-4da4-b620-fd8d735cfac0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_O2023ADividendsMember_9fddc1ca-82d8-4924-9cca-9a3f8c22072c" xlink:href="unit-20241231.xsd#unit_O2023ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_O2023ADividendsMember_9fddc1ca-82d8-4924-9cca-9a3f8c22072c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_O2022ADividendsMember_26b3f4f7-f074-49bc-b912-eab421ebc9c6" xlink:href="unit-20241231.xsd#unit_O2022ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_O2022ADividendsMember_26b3f4f7-f074-49bc-b912-eab421ebc9c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_S2024ADividendsMember_8b533d7d-8543-4404-9a3a-14fac24feb04" xlink:href="unit-20241231.xsd#unit_S2024ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_S2024ADividendsMember_8b533d7d-8543-4404-9a3a-14fac24feb04" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_S2023ADividendsMember_3cf67ef4-fac7-4cd9-81c4-8c14755749ab" xlink:href="unit-20241231.xsd#unit_S2023ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_S2023ADividendsMember_3cf67ef4-fac7-4cd9-81c4-8c14755749ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_S2022ADividendsMember_2a57135e-7efa-4c40-bafe-24258b190517" xlink:href="unit-20241231.xsd#unit_S2022ADividendsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsDomain_ccb0b78f-7341-4564-ae0b-be13221c9169" xlink:to="loc_unit_S2022ADividendsMember_2a57135e-7efa-4c40-bafe-24258b190517" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_b51b82fd-2a83-456c-a244-278f6655eb08" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_48aae1b1-61b5-43a3-8fc1-82e741d566df" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_b51b82fd-2a83-456c-a244-278f6655eb08" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CommonStockNonDividendsPerShareCashPaid_92bbd037-a952-447a-93bc-5726f19c9a91" xlink:href="unit-20241231.xsd#unit_CommonStockNonDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_48aae1b1-61b5-43a3-8fc1-82e741d566df" xlink:to="loc_unit_CommonStockNonDividendsPerShareCashPaid_92bbd037-a952-447a-93bc-5726f19c9a91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CommonStockDividendsAndNonDividendsPerShareCashPaid_0702b217-4717-4024-a48d-01b1950ff302" xlink:href="unit-20241231.xsd#unit_CommonStockDividendsAndNonDividendsPerShareCashPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DividendsPayableLineItems_48aae1b1-61b5-43a3-8fc1-82e741d566df" xlink:to="loc_unit_CommonStockDividendsAndNonDividendsPerShareCashPaid_0702b217-4717-4024-a48d-01b1950ff302" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/EmployeeBenefitPlanDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#EmployeeBenefitPlanDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/EmployeeBenefitPlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedContributionPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanTable_2724e282-7efd-4ebe-b62c-77e49eebe9bc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedContributionPlanTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:to="loc_us-gaap_DefinedContributionPlanTable_2724e282-7efd-4ebe-b62c-77e49eebe9bc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis_78735c42-812a-4d90-9265-1ee00c7ada47" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedContributionPlanTable_2724e282-7efd-4ebe-b62c-77e49eebe9bc" xlink:to="loc_us-gaap_RetirementPlanNameAxis_78735c42-812a-4d90-9265-1ee00c7ada47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_78735c42-812a-4d90-9265-1ee00c7ada47_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanNameAxis_78735c42-812a-4d90-9265-1ee00c7ada47" xlink:to="loc_us-gaap_RetirementPlanNameDomain_78735c42-812a-4d90-9265-1ee00c7ada47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_d4ef5e96-260e-4569-b946-cca27bc40dfa" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanNameAxis_78735c42-812a-4d90-9265-1ee00c7ada47" xlink:to="loc_us-gaap_RetirementPlanNameDomain_d4ef5e96-260e-4569-b946-cca27bc40dfa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DefinedContributionPlanFirstThreePercentOfEmployeesCompensationMember_9fe8901b-e641-4d7f-ac1b-2f2fc009c40a" xlink:href="unit-20241231.xsd#unit_DefinedContributionPlanFirstThreePercentOfEmployeesCompensationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_d4ef5e96-260e-4569-b946-cca27bc40dfa" xlink:to="loc_unit_DefinedContributionPlanFirstThreePercentOfEmployeesCompensationMember_9fe8901b-e641-4d7f-ac1b-2f2fc009c40a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DefinedContributionPlanNextTwoPercentOfEmployeesCompensationMember_c08c423e-69ba-425a-a1f0-6fc617ff7079" xlink:href="unit-20241231.xsd#unit_DefinedContributionPlanNextTwoPercentOfEmployeesCompensationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_d4ef5e96-260e-4569-b946-cca27bc40dfa" xlink:to="loc_unit_DefinedContributionPlanNextTwoPercentOfEmployeesCompensationMember_c08c423e-69ba-425a-a1f0-6fc617ff7079" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_DefinedContributionPlanEmployeeMinimumAge_36d28c4d-56e6-49b0-8256-b6d400042fd5" xlink:href="unit-20241231.xsd#unit_DefinedContributionPlanEmployeeMinimumAge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:to="loc_unit_DefinedContributionPlanEmployeeMinimumAge_36d28c4d-56e6-49b0-8256-b6d400042fd5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_f45d6dff-d544-4452-957d-6b22302a167c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_f45d6dff-d544-4452-957d-6b22302a167c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_e7b93834-7722-4737-926a-68d76a3b152f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:to="loc_us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_e7b93834-7722-4737-926a-68d76a3b152f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_cdcd1c2c-7ab8-4254-87d6-2cf845077cfc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedContributionPlanDisclosureLineItems_99fa8713-f98e-433e-8b38-d820fe42a0d1" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_cdcd1c2c-7ab8-4254-87d6-2cf845077cfc" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatedBalanceSheetInformationReflectingtheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatedBalanceSheetInformationReflectingtheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatedBalanceSheetInformationReflectingtheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cd2301b0-07f5-4493-b734-f894092db903" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_789bd14d-93e6-4139-a82d-888a00eb5272" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cd2301b0-07f5-4493-b734-f894092db903" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_789bd14d-93e6-4139-a82d-888a00eb5272" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_b57de582-7baf-4fcb-adf6-e49859e185b9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_789bd14d-93e6-4139-a82d-888a00eb5272" xlink:to="loc_srt_ConsolidatedEntitiesAxis_b57de582-7baf-4fcb-adf6-e49859e185b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_b57de582-7baf-4fcb-adf6-e49859e185b9_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_b57de582-7baf-4fcb-adf6-e49859e185b9" xlink:to="loc_srt_ConsolidatedEntitiesDomain_b57de582-7baf-4fcb-adf6-e49859e185b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_4b700f84-c462-466d-98be-7b4c5cecba58" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_b57de582-7baf-4fcb-adf6-e49859e185b9" xlink:to="loc_srt_ConsolidatedEntitiesDomain_4b700f84-c462-466d-98be-7b4c5cecba58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SubsidiariesMember_5b0c1c90-b855-42f7-bc80-42bc149defc3" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_4b700f84-c462-466d-98be-7b4c5cecba58" xlink:to="loc_srt_SubsidiariesMember_5b0c1c90-b855-42f7-bc80-42bc149defc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NonGuarantorSubsidiariesMember_1db0e5b0-b209-441f-a74b-bbd46daab77e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NonGuarantorSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SubsidiariesMember_5b0c1c90-b855-42f7-bc80-42bc149defc3" xlink:to="loc_srt_NonGuarantorSubsidiariesMember_1db0e5b0-b209-441f-a74b-bbd46daab77e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_GuarantorSubsidiariesMember_0b5061d7-a15f-44a7-874c-097cabd10704" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_GuarantorSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SubsidiariesMember_5b0c1c90-b855-42f7-bc80-42bc149defc3" xlink:to="loc_srt_GuarantorSubsidiariesMember_0b5061d7-a15f-44a7-874c-097cabd10704" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_2e0a096c-6953-45bd-81f4-4886bbd52bfc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_789bd14d-93e6-4139-a82d-888a00eb5272" xlink:to="loc_srt_ConsolidationItemsAxis_2e0a096c-6953-45bd-81f4-4886bbd52bfc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_2e0a096c-6953-45bd-81f4-4886bbd52bfc_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_2e0a096c-6953-45bd-81f4-4886bbd52bfc" xlink:to="loc_srt_ConsolidationItemsDomain_2e0a096c-6953-45bd-81f4-4886bbd52bfc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_83866957-6190-441d-92f1-c1458d2a86dc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_2e0a096c-6953-45bd-81f4-4886bbd52bfc" xlink:to="loc_srt_ConsolidationItemsDomain_83866957-6190-441d-92f1-c1458d2a86dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_03a168d5-9060-4041-8c85-6c3d68d9d4fc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_83866957-6190-441d-92f1-c1458d2a86dc" xlink:to="loc_srt_ConsolidationEliminationsMember_03a168d5-9060-4041-8c85-6c3d68d9d4fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cd2301b0-07f5-4493-b734-f894092db903" xlink:to="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9d96ad16-dc95-44d1-b578-d018d0e16e6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_9d96ad16-dc95-44d1-b578-d018d0e16e6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_c7c63628-a955-4619-b644-076451663685" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_c7c63628-a955-4619-b644-076451663685" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalents_64d7312d-63a0-4bb1-a141-957faef164f5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RestrictedCashAndCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalents_64d7312d-63a0-4bb1-a141-957faef164f5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_6a3aa4f4-b7bb-4e35-8b73-490a00eb34e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_AccountsReceivableNet_6a3aa4f4-b7bb-4e35-8b73-490a00eb34e5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_934c53fe-0e0e-4c85-96e0-3a66109f5829" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_Goodwill_934c53fe-0e0e-4c85-96e0-3a66109f5829" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_1ae90fc5-9dc0-467e-8f46-f16332b80e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_1ae90fc5-9dc0-467e-8f46-f16332b80e7b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRentReceivablesNet_ace75f22-0b3c-42db-b97c-999a8bd97796" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredRentReceivablesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_DeferredRentReceivablesNet_ace75f22-0b3c-42db-b97c-999a8bd97796" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_28c7499a-a480-41a3-92d0-55c295a5f50b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_28c7499a-a480-41a3-92d0-55c295a5f50b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_e24ec7ec-fbec-4e0c-8441-8166b82bd56e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_OtherAssets_e24ec7ec-fbec-4e0c-8441-8166b82bd56e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet_a2ed9ddc-b96c-42d0-b71a-6e8e34942863" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_DeferredIncomeTaxAssetsNet_a2ed9ddc-b96c-42d0-b71a-6e8e34942863" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_917ba007-118f-416a-a15f-4e59ea7df62c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_DerivativeAssets_917ba007-118f-416a-a15f-4e59ea7df62c" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_d2ca6fae-578f-4c2f-b6cc-5dd5e7e7cb6c" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_98176b93-e9d7-418d-b6d0-555550c99323" xlink:to="loc_us-gaap_Assets_d2ca6fae-578f-4c2f-b6cc-5dd5e7e7cb6c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d9ab3bee-b421-423c-9a32-8280bfc287cf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cd2301b0-07f5-4493-b734-f894092db903" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d9ab3bee-b421-423c-9a32-8280bfc287cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d9ab3bee-b421-423c-9a32-8280bfc287cf" xlink:to="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilities_25b9383b-d07f-4a6b-b6a6-de8a3a089fef" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilities_25b9383b-d07f-4a6b-b6a6-de8a3a089fef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_SettlementPayable_01677e20-de80-43b5-96fa-8f6c6735ca9f" xlink:href="unit-20241231.xsd#unit_SettlementPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_unit_SettlementPayable_01677e20-de80-43b5-96fa-8f6c6735ca9f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_IntangibleLiabilitiesNet_8487da1e-fd64-4948-b110-7ce9f37aa3ad" xlink:href="unit-20241231.xsd#unit_IntangibleLiabilitiesNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_unit_IntangibleLiabilitiesNet_8487da1e-fd64-4948-b110-7ce9f37aa3ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPayableCurrentAndNoncurrent_a33d7296-bd32-467f-90de-fd3ee4c4b9f2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_InterestPayableCurrentAndNoncurrent_a33d7296-bd32-467f-90de-fd3ee4c4b9f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredRevenue_915f5126-9886-4f87-8666-d891311529f3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DeferredRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_DeferredRevenue_915f5126-9886-4f87-8666-d891311529f3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_ec39b7c6-0c11-4a83-8f96-79a17893f6d3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_ec39b7c6-0c11-4a83-8f96-79a17893f6d3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_35e1e5a2-19e0-4ca4-8a3d-8ab442ba7a35" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_OperatingLeaseLiability_35e1e5a2-19e0-4ca4-8a3d-8ab442ba7a35" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale_5c804b02-291b-4a60-8a0a-b2fc3397cb93" xlink:href="unit-20241231.xsd#unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale_5c804b02-291b-4a60-8a0a-b2fc3397cb93" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_c7a1b6b7-585f-4167-8fa1-d9b46a8ee44e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_LongTermDebt_c7a1b6b7-585f-4167-8fa1-d9b46a8ee44e" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_7b55e7e1-99a0-44c3-97e7-76400df9aeb4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_048d40fb-44dc-49bf-abeb-d4e15c11a40b" xlink:to="loc_us-gaap_Liabilities_7b55e7e1-99a0-44c3-97e7-76400df9aeb4" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_4806ba9e-ee82-4a8a-a739-e2186a54b64e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d9ab3bee-b421-423c-9a32-8280bfc287cf" xlink:to="loc_us-gaap_StockholdersEquityAbstract_4806ba9e-ee82-4a8a-a739-e2186a54b64e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_d8249b80-7ca7-45dd-8799-ee0b7df0e4bf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_4806ba9e-ee82-4a8a-a739-e2186a54b64e" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_d8249b80-7ca7-45dd-8799-ee0b7df0e4bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_52f83c42-886c-42c1-86bc-9d499d2e0a70" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d9ab3bee-b421-423c-9a32-8280bfc287cf" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_52f83c42-886c-42c1-86bc-9d499d2e0a70" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatingStatementofOperationsInformationReflectingTheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatingStatementofOperationsInformationReflectingTheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SupplementaryUnrestrictedSubsidiaryInformationScheduleofConsolidatingStatementofOperationsInformationReflectingTheEliminationoftheAccountsofUnrestrictedSubsidiariesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedIncomeStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedIncomeStatementTable_8a6f2e36-4dda-472b-afd3-25367c8d252b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedIncomeStatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_srt_CondensedIncomeStatementTable_8a6f2e36-4dda-472b-afd3-25367c8d252b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_2dbab4c6-01a2-4f08-9238-3e67b68cf83f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedIncomeStatementTable_8a6f2e36-4dda-472b-afd3-25367c8d252b" xlink:to="loc_srt_ConsolidatedEntitiesAxis_2dbab4c6-01a2-4f08-9238-3e67b68cf83f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_2dbab4c6-01a2-4f08-9238-3e67b68cf83f_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_2dbab4c6-01a2-4f08-9238-3e67b68cf83f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_2dbab4c6-01a2-4f08-9238-3e67b68cf83f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_bca388e3-711d-482f-8042-baf696746571" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_2dbab4c6-01a2-4f08-9238-3e67b68cf83f" xlink:to="loc_srt_ConsolidatedEntitiesDomain_bca388e3-711d-482f-8042-baf696746571" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SubsidiariesMember_d0c230ff-be89-4efb-a047-16e8b5b3bf5f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_SubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_bca388e3-711d-482f-8042-baf696746571" xlink:to="loc_srt_SubsidiariesMember_d0c230ff-be89-4efb-a047-16e8b5b3bf5f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NonGuarantorSubsidiariesMember_53716fd7-3e3f-48e3-aaa5-978f9052acfc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NonGuarantorSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SubsidiariesMember_d0c230ff-be89-4efb-a047-16e8b5b3bf5f" xlink:to="loc_srt_NonGuarantorSubsidiariesMember_53716fd7-3e3f-48e3-aaa5-978f9052acfc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_GuarantorSubsidiariesMember_cd0f9bf9-9643-43ab-8c1a-42f5bb280f30" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_GuarantorSubsidiariesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SubsidiariesMember_d0c230ff-be89-4efb-a047-16e8b5b3bf5f" xlink:to="loc_srt_GuarantorSubsidiariesMember_cd0f9bf9-9643-43ab-8c1a-42f5bb280f30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_20145b12-8629-4b71-88ce-c799d8c00259" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_CondensedIncomeStatementTable_8a6f2e36-4dda-472b-afd3-25367c8d252b" xlink:to="loc_srt_ConsolidationItemsAxis_20145b12-8629-4b71-88ce-c799d8c00259" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_20145b12-8629-4b71-88ce-c799d8c00259_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_20145b12-8629-4b71-88ce-c799d8c00259" xlink:to="loc_srt_ConsolidationItemsDomain_20145b12-8629-4b71-88ce-c799d8c00259_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_ec820cf3-4c07-44b6-9542-55b51c1c437f" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_20145b12-8629-4b71-88ce-c799d8c00259" xlink:to="loc_srt_ConsolidationItemsDomain_ec820cf3-4c07-44b6-9542-55b51c1c437f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationEliminationsMember_79554cf1-b5eb-483d-9dbd-76825d7caecf" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidationEliminationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_ec820cf3-4c07-44b6-9542-55b51c1c437f" xlink:to="loc_srt_ConsolidationEliminationsMember_79554cf1-b5eb-483d-9dbd-76825d7caecf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_cae5b881-a143-42ba-80d4-63ecdda25936" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_us-gaap_RevenuesAbstract_cae5b881-a143-42ba-80d4-63ecdda25936" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_c028e38a-54ba-45fb-bcf2-d5a6e376da37" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_cae5b881-a143-42ba-80d4-63ecdda25936" xlink:to="loc_us-gaap_Revenues_c028e38a-54ba-45fb-bcf2-d5a6e376da37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_e51f7e5c-772e-4446-957f-dc0f91a583fd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_InterestExpense_e51f7e5c-772e-4446-957f-dc0f91a583fd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_74be3520-9a4e-464e-a298-2ddbc8c41dcd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_DepreciationAndAmortization_74be3520-9a4e-464e-a298-2ddbc8c41dcd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_514fa492-4a65-486d-972d-80e0bbfc687f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_514fa492-4a65-486d-972d-80e0bbfc687f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_8dc966cb-076c-4299-a0fc-3d9bec24c283" xlink:href="unit-20241231.xsd#unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_unit_OperatingExpenseExclusiveOfDepreciationAccretionAndAmortization_8dc966cb-076c-4299-a0fc-3d9bec24c283" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TransactionRelatedAndOtherCosts_62db955e-9696-4b0a-8d0e-d51fe373085d" xlink:href="unit-20241231.xsd#unit_TransactionRelatedAndOtherCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_unit_TransactionRelatedAndOtherCosts_62db955e-9696-4b0a-8d0e-d51fe373085d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_8188d6e3-2a6f-44d1-b335-16e1281f0baf" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GainsLossesOnSalesOfInvestmentRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_GainsLossesOnSalesOfInvestmentRealEstate_8188d6e3-2a6f-44d1-b335-16e1281f0baf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherOperatingIncomeExpenseNet_9193f64f-2001-44b7-a5ed-6bdba3a40a0f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherOperatingIncomeExpenseNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_OtherOperatingIncomeExpenseNet_9193f64f-2001-44b7-a5ed-6bdba3a40a0f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_0362bccd-a0ab-4ab6-bf50-639b969068e4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_f35683cb-262e-4e8d-abac-7ff0892cdc8f" xlink:to="loc_us-gaap_CostsAndExpenses_0362bccd-a0ab-4ab6-bf50-639b969068e4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_55004e96-5266-46d8-99f1-9ff653d2119b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments_55004e96-5266-46d8-99f1-9ff653d2119b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_8bc5c75e-d5ae-4f27-aac3-dca3302c7af1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_8bc5c75e-d5ae-4f27-aac3-dca3302c7af1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_1dcbd89e-2978-4d65-ad57-48e9fc2d32ba" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedIncomeStatementsCaptionsLineItems_b40bc769-d0e2-4777-9f4e-5e2e831a069b" xlink:to="loc_us-gaap_ProfitLoss_1dcbd89e-2978-4d65-ad57-48e9fc2d32ba" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#SubsequentEventsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_eac2e8f6-a994-4bfb-ae5f-aec07155e917" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_0ea5b674-e048-4c1e-8767-624ce8812841" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_eac2e8f6-a994-4bfb-ae5f-aec07155e917" xlink:to="loc_us-gaap_SubsequentEventTable_0ea5b674-e048-4c1e-8767-624ce8812841" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_111efd8a-cc83-4514-afc2-26ce4bcd48a3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_0ea5b674-e048-4c1e-8767-624ce8812841" xlink:to="loc_us-gaap_DebtInstrumentAxis_111efd8a-cc83-4514-afc2-26ce4bcd48a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_111efd8a-cc83-4514-afc2-26ce4bcd48a3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_111efd8a-cc83-4514-afc2-26ce4bcd48a3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_111efd8a-cc83-4514-afc2-26ce4bcd48a3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_8ce4ba14-08a7-4c69-a28c-7e1325aa92d9" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_111efd8a-cc83-4514-afc2-26ce4bcd48a3" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_8ce4ba14-08a7-4c69-a28c-7e1325aa92d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ABSNotesMember_cb14f213-2c80-449b-8e39-cf284dd3615b" xlink:href="unit-20241231.xsd#unit_ABSNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_8ce4ba14-08a7-4c69-a28c-7e1325aa92d9" xlink:to="loc_unit_ABSNotesMember_cb14f213-2c80-449b-8e39-cf284dd3615b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_4e2478f7-ad12-4104-a0e9-65da999a068b" xlink:href="unit-20241231.xsd#unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_8ce4ba14-08a7-4c69-a28c-7e1325aa92d9" xlink:to="loc_unit_TenPointFivePercentageSeniorNotesDueFebruaryFifteenTwoThousandTwentyEightMember_4e2478f7-ad12-4104-a0e9-65da999a068b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_ffa836a5-0f4c-4a16-a65c-9383ca908733" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_0ea5b674-e048-4c1e-8767-624ce8812841" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_ffa836a5-0f4c-4a16-a65c-9383ca908733" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ffa836a5-0f4c-4a16-a65c-9383ca908733_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ffa836a5-0f4c-4a16-a65c-9383ca908733" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ffa836a5-0f4c-4a16-a65c-9383ca908733_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_ae4b7d2c-9b34-4823-b84b-a660c9246c70" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_ffa836a5-0f4c-4a16-a65c-9383ca908733" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_ae4b7d2c-9b34-4823-b84b-a660c9246c70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_6f451a92-55f2-46b7-8aef-c2bbd641dba4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_ae4b7d2c-9b34-4823-b84b-a660c9246c70" xlink:to="loc_us-gaap_SecuredDebtMember_6f451a92-55f2-46b7-8aef-c2bbd641dba4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_b192b85f-3281-487b-b97a-42d35c8cd71e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_0ea5b674-e048-4c1e-8767-624ce8812841" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_b192b85f-3281-487b-b97a-42d35c8cd71e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_b192b85f-3281-487b-b97a-42d35c8cd71e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_b192b85f-3281-487b-b97a-42d35c8cd71e" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_b192b85f-3281-487b-b97a-42d35c8cd71e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_484ddff0-c29a-4a39-a5df-987566e16f41" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_b192b85f-3281-487b-b97a-42d35c8cd71e" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_484ddff0-c29a-4a39-a5df-987566e16f41" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_4b408502-f52f-4f16-814a-cf0245cf31f0" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_484ddff0-c29a-4a39-a5df-987566e16f41" xlink:to="loc_us-gaap_SubsequentEventMember_4b408502-f52f-4f16-814a-cf0245cf31f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_3d9ae1a8-431e-47a3-ab45-45f83be493ec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_eac2e8f6-a994-4bfb-ae5f-aec07155e917" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_3d9ae1a8-431e-47a3-ab45-45f83be493ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_aa88463d-de69-4ced-899d-3f1b5d508bfb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentRepurchasedFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_eac2e8f6-a994-4bfb-ae5f-aec07155e917" xlink:to="loc_us-gaap_DebtInstrumentRepurchasedFaceAmount_aa88463d-de69-4ced-899d-3f1b5d508bfb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_be05acec-5471-4578-8aac-6610de85cd7e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_eac2e8f6-a994-4bfb-ae5f-aec07155e917" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_be05acec-5471-4578-8aac-6610de85cd7e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedBalanceSheetsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedBalanceSheetsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4803d7aa-7629-441d-a6b8-f6da5a2da943" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4803d7aa-7629-441d-a6b8-f6da5a2da943" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4803d7aa-7629-441d-a6b8-f6da5a2da943" xlink:to="loc_srt_ConsolidatedEntitiesAxis_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e" xlink:to="loc_srt_ConsolidatedEntitiesDomain_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_c5b617ae-fbdc-4fb3-81ab-c656c31d5c58" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_ed4f7816-88a4-4d31-9a1a-170a8c2a8c5e" xlink:to="loc_srt_ConsolidatedEntitiesDomain_c5b617ae-fbdc-4fb3-81ab-c656c31d5c58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_4b04c34c-d332-40d4-8ab6-caa56b55b323" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_c5b617ae-fbdc-4fb3-81ab-c656c31d5c58" xlink:to="loc_srt_ParentCompanyMember_4b04c34c-d332-40d4-8ab6-caa56b55b323" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_cc50441c-dd6e-48d5-9507-0a11062a2d9b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_AssetsAbstract_cc50441c-dd6e-48d5-9507-0a11062a2d9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_59029ff3-1d22-422b-afdc-d902f7214115" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_cc50441c-dd6e-48d5-9507-0a11062a2d9b" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_59029ff3-1d22-422b-afdc-d902f7214115" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_8c124be5-3e74-434f-a549-82193f153d99" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract_cc50441c-dd6e-48d5-9507-0a11062a2d9b" xlink:to="loc_us-gaap_Assets_8c124be5-3e74-434f-a549-82193f153d99" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent_be310222-f6e5-47fa-be9c-64dfb48fb6eb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrentAndNoncurrent_be310222-f6e5-47fa-be9c-64dfb48fb6eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_428f51e6-0ad0-45b9-aeee-adfa39a88fe7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:to="loc_us-gaap_DividendsPayableCurrentAndNoncurrent_428f51e6-0ad0-45b9-aeee-adfa39a88fe7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_b0d8da38-5c91-4877-a24b-1c1214c31c2d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:to="loc_us-gaap_LongTermDebt_b0d8da38-5c91-4877-a24b-1c1214c31c2d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CashDistributionsAndLossesInExcessOfInvestmentsInSubsidiaries_befcba3c-a3bb-49c1-918b-94027c732512" xlink:href="unit-20241231.xsd#unit_CashDistributionsAndLossesInExcessOfInvestmentsInSubsidiaries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:to="loc_unit_CashDistributionsAndLossesInExcessOfInvestmentsInSubsidiaries_befcba3c-a3bb-49c1-918b-94027c732512" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_476489ff-6971-453e-9107-a3f5374c07f1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_919f3c26-3517-44ee-ac21-b19dbbaaf135" xlink:to="loc_us-gaap_Liabilities_476489ff-6971-453e-9107-a3f5374c07f1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockValue_9fcf2c1f-d816-47cc-98e5-a9b25dbf4346" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_PreferredStockValue_9fcf2c1f-d816-47cc-98e5-a9b25dbf4346" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_d24f326a-082e-434a-a143-a640f041c749" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_CommonStockValue_d24f326a-082e-434a-a143-a640f041c749" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_3063bc48-2a55-436a-b259-865d62a0ee94" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_3063bc48-2a55-436a-b259-865d62a0ee94" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_c1d6d477-7591-429d-9ab0-f501c7260a8d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_c1d6d477-7591-429d-9ab0-f501c7260a8d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_43efcee5-75c8-4f4b-881b-9cb3c38dd274" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_43efcee5-75c8-4f4b-881b-9cb3c38dd274" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_a77aa6a2-be7b-4d16-a4a7-ad9e745400b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StockholdersEquityAbstract_d18917ff-c9bd-4b46-a273-fe40e0dadc0a" xlink:to="loc_us-gaap_StockholdersEquity_a77aa6a2-be7b-4d16-a4a7-ad9e745400b2" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_9cbeef86-dee3-4fbb-b364-59c398edc465" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_9cbeef86-dee3-4fbb-b364-59c398edc465" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare_42883c92-1f37-43cd-8bca-25227a0f1d7b" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_PreferredStockParOrStatedValuePerShare_42883c92-1f37-43cd-8bca-25227a0f1d7b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_292d5217-f319-4022-a3e5-a8278ee3444a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_292d5217-f319-4022-a3e5-a8278ee3444a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesIssued_8a9810c2-7717-48cc-9374-f45d0e9a817f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_PreferredStockSharesIssued_8a9810c2-7717-48cc-9374-f45d0e9a817f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_64247125-45fe-43a8-95bf-f0e872098d49" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_64247125-45fe-43a8-95bf-f0e872098d49" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_4edaee05-a8bb-4b89-b9ad-8f4e774f848e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_4edaee05-a8bb-4b89-b9ad-8f4e774f848e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_b7a3754d-6f06-4354-b4d4-6daf9cc9eb7d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_b7a3754d-6f06-4354-b4d4-6daf9cc9eb7d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_e2f5b726-f434-4609-bb4f-d0741fa5e813" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_CommonStockSharesIssued_e2f5b726-f434-4609-bb4f-d0741fa5e813" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_69a733ad-151a-4c22-9380-67b7a0a203d8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_9e620e76-fef0-4fe1-98e6-1ab279c93c22" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_69a733ad-151a-4c22-9380-67b7a0a203d8" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofComprehensiveIncomeLossDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofComprehensiveIncomeLossDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofComprehensiveIncomeLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4e61a636-7f96-4305-9eb8-c354c4fb246d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4e61a636-7f96-4305-9eb8-c354c4fb246d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_d2ece97d-6519-43c5-8dff-e0718284214d" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_4e61a636-7f96-4305-9eb8-c354c4fb246d" xlink:to="loc_srt_ConsolidatedEntitiesAxis_d2ece97d-6519-43c5-8dff-e0718284214d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_d2ece97d-6519-43c5-8dff-e0718284214d_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_d2ece97d-6519-43c5-8dff-e0718284214d" xlink:to="loc_srt_ConsolidatedEntitiesDomain_d2ece97d-6519-43c5-8dff-e0718284214d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_b87145b0-72c5-4a81-9ddf-13e8969a60d5" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_d2ece97d-6519-43c5-8dff-e0718284214d" xlink:to="loc_srt_ConsolidatedEntitiesDomain_b87145b0-72c5-4a81-9ddf-13e8969a60d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_b0b28cf0-6a36-4337-99c1-6db70edfb539" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_b87145b0-72c5-4a81-9ddf-13e8969a60d5" xlink:to="loc_srt_ParentCompanyMember_b0b28cf0-6a36-4337-99c1-6db70edfb539" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_1415754f-adee-4aab-a452-40bb13b355b8" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:to="loc_us-gaap_InterestExpense_1415754f-adee-4aab-a452-40bb13b355b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_7fe15c9b-d236-41c5-a65b-c469a2dd0189" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_7fe15c9b-d236-41c5-a65b-c469a2dd0189" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TransactionRelatedCost_9947b8a2-50dc-4ef7-b5a3-1863484edf25" xlink:href="unit-20241231.xsd#unit_TransactionRelatedCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:to="loc_unit_TransactionRelatedCost_9947b8a2-50dc-4ef7-b5a3-1863484edf25" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_7ea2c641-6767-46b8-afef-af4bcc13d7ab" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_a53e0147-71a3-4e03-a1d6-a66a630b3f99" xlink:to="loc_us-gaap_CostsAndExpenses_7ea2c641-6767-46b8-afef-af4bcc13d7ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_e3378932-14a1-44eb-907d-066654696ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_OperatingIncomeLoss_e3378932-14a1-44eb-907d-066654696ec1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_2c2a21ce-4d08-4137-898a-0ee552df5025" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_2c2a21ce-4d08-4137-898a-0ee552df5025" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8502d15d-5fe7-43aa-adbe-16062bec15e5" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_8502d15d-5fe7-43aa-adbe-16062bec15e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_009861ce-da95-4003-84fc-ef8ecbc17029" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_009861ce-da95-4003-84fc-ef8ecbc17029" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_d9dc799c-c865-4c90-a397-b3451edfea9e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_NetIncomeLoss_d9dc799c-c865-4c90-a397-b3451edfea9e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_e9d794ec-1f08-4f52-9345-836231173ded" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_225adabd-40b1-4518-9acc-f7a3afe6e208" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_e9d794ec-1f08-4f52-9345-836231173ded" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofCashFlowsDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofCashFlowsDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleICondensedFinancialInformationofTheRegistrantParentCompanyCondensedStatementsofCashFlowsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_52019569-277e-4691-b34b-5136d0f5f242" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_52019569-277e-4691-b34b-5136d0f5f242" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_6dd42b4c-aa21-4b99-96cc-3ce7c95af670" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_52019569-277e-4691-b34b-5136d0f5f242" xlink:to="loc_srt_ConsolidatedEntitiesAxis_6dd42b4c-aa21-4b99-96cc-3ce7c95af670" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_6dd42b4c-aa21-4b99-96cc-3ce7c95af670_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_6dd42b4c-aa21-4b99-96cc-3ce7c95af670" xlink:to="loc_srt_ConsolidatedEntitiesDomain_6dd42b4c-aa21-4b99-96cc-3ce7c95af670_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_f01086a1-78e8-4b27-8869-facd495834ff" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_6dd42b4c-aa21-4b99-96cc-3ce7c95af670" xlink:to="loc_srt_ConsolidatedEntitiesDomain_f01086a1-78e8-4b27-8869-facd495834ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_53e2de15-d8a8-42e2-8597-7ec36d031e88" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_f01086a1-78e8-4b27-8869-facd495834ff" xlink:to="loc_srt_ParentCompanyMember_53e2de15-d8a8-42e2-8597-7ec36d031e88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0c2b4d9b-8659-447f-a2c8-4a8c647bba43" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0c2b4d9b-8659-447f-a2c8-4a8c647bba43" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_473070b9-4412-4d41-980b-eb4555dae6cb" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_0c2b4d9b-8659-447f-a2c8-4a8c647bba43" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_473070b9-4412-4d41-980b-eb4555dae6cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_059a16e2-f479-462b-8011-cd533981d178" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_059a16e2-f479-462b-8011-cd533981d178" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ProceedsFromRealEstateSale_cdd79de0-9770-40e1-ae2d-f33cc37c0a94" xlink:href="unit-20241231.xsd#unit_ProceedsFromRealEstateSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_059a16e2-f479-462b-8011-cd533981d178" xlink:to="loc_unit_ProceedsFromRealEstateSale_cdd79de0-9770-40e1-ae2d-f33cc37c0a94" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_c2454e0f-040d-4a00-add8-278d273b4024" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_059a16e2-f479-462b-8011-cd533981d178" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_c2454e0f-040d-4a00-add8-278d273b4024" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDividendsCommonStock_9ad8079c-e0c4-4d69-8ac9-9fcdf027cec7" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsOfDividendsCommonStock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_PaymentsOfDividendsCommonStock_9ad8079c-e0c4-4d69-8ac9-9fcdf027cec7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromNotesPayable_bc932c2f-d923-4f20-b11c-0d1439168e77" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromNotesPayable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_ProceedsFromNotesPayable_bc932c2f-d923-4f20-b11c-0d1439168e77" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfFinancingCosts_67486ff3-ee57-4bad-87d5-21a9ee312ff3" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsOfFinancingCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_PaymentsOfFinancingCosts_67486ff3-ee57-4bad-87d5-21a9ee312ff3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ProceedsFromIssuanceOfStockNetOfIssuanceCosts_a6721c8b-79bf-41ea-815b-8e988831d95b" xlink:href="unit-20241231.xsd#unit_ProceedsFromIssuanceOfStockNetOfIssuanceCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_unit_ProceedsFromIssuanceOfStockNetOfIssuanceCosts_a6721c8b-79bf-41ea-815b-8e988831d95b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_1875d60d-b718-4d75-a318-5e1b97b73732" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation_1875d60d-b718-4d75-a318-5e1b97b73732" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfWarrants_61b0b205-deee-463e-96bf-dfcf2f961a3d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromIssuanceOfWarrants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfWarrants_61b0b205-deee-463e-96bf-dfcf2f961a3d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForHedgeFinancingActivities_59608923-b543-42b8-bc2d-3899fb14a9f4" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PaymentsForHedgeFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_PaymentsForHedgeFinancingActivities_59608923-b543-42b8-bc2d-3899fb14a9f4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_IntercompanyTransactionsNet_c6ed0c12-5cfa-4f3b-92e1-9d6330170413" xlink:href="unit-20241231.xsd#unit_IntercompanyTransactionsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_unit_IntercompanyTransactionsNet_c6ed0c12-5cfa-4f3b-92e1-9d6330170413" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockPlans_8062a6a5-3f97-47ed-9e5e-ab0066a96015" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ProceedsFromStockPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_ProceedsFromStockPlans_8062a6a5-3f97-47ed-9e5e-ab0066a96015" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_d6968702-efdb-4574-be7e-cb4c17111578" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_c1b89875-91c7-4a5b-9370-06f14ff8e42d" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_d6968702-efdb-4574-be7e-cb4c17111578" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_2ca8e18e-b1ce-4947-ae92-5fa50c750147" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_2ca8e18e-b1ce-4947-ae92-5fa50c750147" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_e344d6cc-96cc-49b6-b916-a9f9b1463577" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_cecbf9e8-47fb-49dd-be13-ab5f2f9f7814" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_e344d6cc-96cc-49b6-b916-a9f9b1463577" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_daf562a0-7ca3-44df-a0d6-787ea1d11d19" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleIAdditionalInformationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleIAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleIAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_CondensedFinancialStatementsCaptionsLineItems_7a9d3207-2b94-436c-968a-fbbef7e7fdcc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CondensedFinancialStatementsCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfCondensedFinancialStatementsTable_81fe1a9a-7741-40e8-b846-bf5033ae0076" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ScheduleOfCondensedFinancialStatementsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_7a9d3207-2b94-436c-968a-fbbef7e7fdcc" xlink:to="loc_srt_ScheduleOfCondensedFinancialStatementsTable_81fe1a9a-7741-40e8-b846-bf5033ae0076" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_3e402cca-9190-4fc3-9ce8-5e97f5a783b9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_81fe1a9a-7741-40e8-b846-bf5033ae0076" xlink:to="loc_srt_OwnershipAxis_3e402cca-9190-4fc3-9ce8-5e97f5a783b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_3e402cca-9190-4fc3-9ce8-5e97f5a783b9_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_3e402cca-9190-4fc3-9ce8-5e97f5a783b9" xlink:to="loc_srt_OwnershipDomain_3e402cca-9190-4fc3-9ce8-5e97f5a783b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_33c8b4ed-69b2-4f24-b15b-e41e69e02324" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_3e402cca-9190-4fc3-9ce8-5e97f5a783b9" xlink:to="loc_srt_OwnershipDomain_33c8b4ed-69b2-4f24-b15b-e41e69e02324" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_UnitiGroupLPMember_8039fca2-bab0-424e-a4f5-b53287f501fb" xlink:href="unit-20241231.xsd#unit_UnitiGroupLPMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_33c8b4ed-69b2-4f24-b15b-e41e69e02324" xlink:to="loc_unit_UnitiGroupLPMember_8039fca2-bab0-424e-a4f5-b53287f501fb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ScheduleOfCondensedFinancialStatementsTable_81fe1a9a-7741-40e8-b846-bf5033ae0076" xlink:to="loc_srt_ConsolidatedEntitiesAxis_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad" xlink:to="loc_srt_ConsolidatedEntitiesDomain_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_255d62f1-d1d6-460e-b92f-df50f406b9f8" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_63d5ecff-ee38-4dc9-ada1-65c0d4c9a7ad" xlink:to="loc_srt_ConsolidatedEntitiesDomain_255d62f1-d1d6-460e-b92f-df50f406b9f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember_48c69e79-af5d-418f-91e6-f8ab07d9edc9" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ParentCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_255d62f1-d1d6-460e-b92f-df50f406b9f8" xlink:to="loc_srt_ParentCompanyMember_48c69e79-af5d-418f-91e6-f8ab07d9edc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_d9371b49-d3c9-4824-a820-20b670040443" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_7a9d3207-2b94-436c-968a-fbbef7e7fdcc" xlink:to="loc_us-gaap_LimitedLiabilityCompanyLLCOrLimitedPartnershipLPManagingMemberOrGeneralPartnerOwnershipInterest_d9371b49-d3c9-4824-a820-20b670040443" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries_494bce49-df63-4e51-a4a0-2cb510f89d32" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CondensedFinancialStatementsCaptionsLineItems_7a9d3207-2b94-436c-968a-fbbef7e7fdcc" xlink:to="loc_us-gaap_CashDividendsPaidToParentCompanyByConsolidatedSubsidiaries_494bce49-df63-4e51-a4a0-2cb510f89d32" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleIIValuationandQualifyingAccountDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleIIValuationandQualifyingAccountDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleIIValuationandQualifyingAccountDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_b7bc64cf-a23d-476a-8d1c-e91e0ceb7188" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_fb66c388-b207-4787-91c6-2ef9b26ed5fc" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_b7bc64cf-a23d-476a-8d1c-e91e0ceb7188" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_fb66c388-b207-4787-91c6-2ef9b26ed5fc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_9dea27e5-b7d1-446d-a461-6ba480166c0a" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_fb66c388-b207-4787-91c6-2ef9b26ed5fc" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_9dea27e5-b7d1-446d-a461-6ba480166c0a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_9dea27e5-b7d1-446d-a461-6ba480166c0a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_9dea27e5-b7d1-446d-a461-6ba480166c0a" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_9dea27e5-b7d1-446d-a461-6ba480166c0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_06a64277-5249-46f1-8623-6b423809a40d" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_9dea27e5-b7d1-446d-a461-6ba480166c0a" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_06a64277-5249-46f1-8623-6b423809a40d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForCreditLossMember_79f118f4-358e-41f9-b688-b01f702122bd" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AllowanceForCreditLossMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_06a64277-5249-46f1-8623-6b423809a40d" xlink:to="loc_us-gaap_AllowanceForCreditLossMember_79f118f4-358e-41f9-b688-b01f702122bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_b7bc64cf-a23d-476a-8d1c-e91e0ceb7188" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_f9d11f65-4169-4e5e-853c-ba80ba923a38" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_f9d11f65-4169-4e5e-853c-ba80ba923a38" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_f655f400-4c54-4009-902d-06ce70254795" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_f655f400-4c54-4009-902d-06ce70254795" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_a66e9675-3d39-4c0b-b6d0-0c23dc379edc" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToOtherAccounts_a66e9675-3d39-4c0b-b6d0-0c23dc379edc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_e883b5ed-3ce5-41ed-ab38-cf38422f79c6" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesDeductions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_b015fe33-ee69-431b-a14e-a31d28705cec" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_e883b5ed-3ce5-41ed-ab38-cf38422f79c6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_d89624a6-ff3b-4e72-aa73-49d887b5fa6f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.uniti.com/role/ScheduleIIIRealEstateInvestmentsandAccumulatedDepreciationDetails" xlink:type="simple" xlink:href="unit-20241231.xsd#ScheduleIIIRealEstateInvestmentsandAccumulatedDepreciationDetails"/>
  <link:definitionLink xlink:role="http://www.uniti.com/role/ScheduleIIIRealEstateInvestmentsandAccumulatedDepreciationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_d482ecc8-c2ca-4218-90fa-30d48cd7781e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateAndAccumulatedDepreciationByPropertyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_d482ecc8-c2ca-4218-90fa-30d48cd7781e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fb81e57d-4797-4314-82d9-e9b602428a5f" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_d482ecc8-c2ca-4218-90fa-30d48cd7781e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fb81e57d-4797-4314-82d9-e9b602428a5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fb81e57d-4797-4314-82d9-e9b602428a5f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fb81e57d-4797-4314-82d9-e9b602428a5f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_fb81e57d-4797-4314-82d9-e9b602428a5f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_fb81e57d-4797-4314-82d9-e9b602428a5f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_31e9d9fa-f353-4452-8703-6564770cef04" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_us-gaap_LandMember_31e9d9fa-f353-4452-8703-6564770cef04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_5e0b9d32-0680-4f3e-b22a-16b54f5b0262" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_5e0b9d32-0680-4f3e-b22a-16b54f5b0262" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_PolesMember_f2ed8635-6301-4d8d-9f3a-131d738e36c2" xlink:href="unit-20241231.xsd#unit_PolesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_unit_PolesMember_f2ed8635-6301-4d8d-9f3a-131d738e36c2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FiberMember_a7ba968f-5ea2-4dfb-a6bc-2051df1894e6" xlink:href="unit-20241231.xsd#unit_FiberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_unit_FiberMember_a7ba968f-5ea2-4dfb-a6bc-2051df1894e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_CopperMember_2a114bd5-fefb-42ec-a449-d909d860cbc3" xlink:href="unit-20241231.xsd#unit_CopperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_unit_CopperMember_2a114bd5-fefb-42ec-a449-d909d860cbc3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_ConduitMember_84edc1be-8f5a-4317-b428-6876493dfd30" xlink:href="unit-20241231.xsd#unit_ConduitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_unit_ConduitMember_84edc1be-8f5a-4317-b428-6876493dfd30" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TowersSegmentMember_f2e83e39-dc41-4823-af28-0a7c6c959630" xlink:href="unit-20241231.xsd#unit_TowersSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_unit_TowersSegmentMember_f2e83e39-dc41-4823-af28-0a7c6c959630" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_c2622d7b-13fb-4344-bbdb-a2642d886664" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_us-gaap_OtherCapitalizedPropertyPlantAndEquipmentMember_c2622d7b-13fb-4344-bbdb-a2642d886664" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_47da991d-55ac-4008-b63e-cb6de6ebec38" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_192c96a4-c2d9-4576-8669-12220d0f49b2" xlink:to="loc_us-gaap_ConstructionInProgressMember_47da991d-55ac-4008-b63e-cb6de6ebec38" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_0867fe4d-e917-4927-9276-b613eb034c9e" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_d482ecc8-c2ca-4218-90fa-30d48cd7781e" xlink:to="loc_srt_RangeAxis_0867fe4d-e917-4927-9276-b613eb034c9e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0867fe4d-e917-4927-9276-b613eb034c9e_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_0867fe4d-e917-4927-9276-b613eb034c9e" xlink:to="loc_srt_RangeMember_0867fe4d-e917-4927-9276-b613eb034c9e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2fa0a59f-1d8c-4387-8a2d-f29e4944f08b" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_0867fe4d-e917-4927-9276-b613eb034c9e" xlink:to="loc_srt_RangeMember_2fa0a59f-1d8c-4387-8a2d-f29e4944f08b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_1e6c5629-bc89-4317-99f6-2694d1f3e20c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2fa0a59f-1d8c-4387-8a2d-f29e4944f08b" xlink:to="loc_srt_MinimumMember_1e6c5629-bc89-4317-99f6-2694d1f3e20c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d02ca05d-20ee-441b-9a4f-1314450c224a" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_2fa0a59f-1d8c-4387-8a2d-f29e4944f08b" xlink:to="loc_srt_MaximumMember_d02ca05d-20ee-441b-9a4f-1314450c224a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_89cdc022-3ed4-4a12-98a6-83613a9638ec" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationByPropertyTable_d482ecc8-c2ca-4218-90fa-30d48cd7781e" xlink:to="loc_srt_MajorCustomersAxis_89cdc022-3ed4-4a12-98a6-83613a9638ec" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_89cdc022-3ed4-4a12-98a6-83613a9638ec_default" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_89cdc022-3ed4-4a12-98a6-83613a9638ec" xlink:to="loc_srt_NameOfMajorCustomerDomain_89cdc022-3ed4-4a12-98a6-83613a9638ec_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_0beca640-c18c-4556-85fd-94da6b394b1c" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_89cdc022-3ed4-4a12-98a6-83613a9638ec" xlink:to="loc_srt_NameOfMajorCustomerDomain_0beca640-c18c-4556-85fd-94da6b394b1c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_WindstreamMember_84bc6179-1c08-425b-b271-c9c57e999a58" xlink:href="unit-20241231.xsd#unit_WindstreamMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_0beca640-c18c-4556-85fd-94da6b394b1c" xlink:to="loc_unit_WindstreamMember_84bc6179-1c08-425b-b271-c9c57e999a58" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateGrossAtCarryingValue_2294caa2-7c44-41a8-a8d5-8382f66a678e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateGrossAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_us-gaap_RealEstateGrossAtCarryingValue_2294caa2-7c44-41a8-a8d5-8382f66a678e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAccumulatedDepreciation_f0d19e8f-e9e0-459a-901b-eef8bad3b14e" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_us-gaap_RealEstateAccumulatedDepreciation_f0d19e8f-e9e0-459a-901b-eef8bad3b14e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_e1a6f668-35c3-47fd-b771-6286199706db" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_us-gaap_RealEstateAndAccumulatedDepreciationLifeUsedForDepreciation1_e1a6f668-35c3-47fd-b771-6286199706db" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_TenantCapitalImprovementsGross_2794a15d-d6ca-4f90-a817-d18da03052c3" xlink:href="unit-20241231.xsd#unit_TenantCapitalImprovementsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_unit_TenantCapitalImprovementsGross_2794a15d-d6ca-4f90-a817-d18da03052c3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_GrowthCapitalImprovements_52fef97f-5ba8-4ab8-8a15-23e4934028a7" xlink:href="unit-20241231.xsd#unit_GrowthCapitalImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_unit_GrowthCapitalImprovements_52fef97f-5ba8-4ab8-8a15-23e4934028a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovements_d385d597-5f7a-4efa-911a-ad63e77000dd" xlink:href="unit-20241231.xsd#unit_NewLeasesAgreementToFundGrowthCapitalImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_unit_NewLeasesAgreementToFundGrowthCapitalImprovements_d385d597-5f7a-4efa-911a-ad63e77000dd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateFederalIncomeTaxBasis_349ac4e8-bc37-4352-acbb-9f20b7efe1f7" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_RealEstateFederalIncomeTaxBasis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationLineItems_7a82a832-1ecb-4385-aa0d-7192bd9dd0ac" xlink:to="loc_srt_RealEstateFederalIncomeTaxBasis_349ac4e8-bc37-4352-acbb-9f20b7efe1f7" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-roles-2024.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset" xlink:type="arc" order="101"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="102"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_LiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2024/elts/us-gaap-2024.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_us-gaap_OperatingLeaseLiability" xlink:type="arc" order="31"/>
    <link:loc xlink:type="locator" xlink:label="loc_unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale_766f7f64-9783-40a4-84f0-8fa98769efd7" xlink:href="unit-20241231.xsd#unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract" xlink:to="loc_unit_FinanceLeaseLiabilityExcludingFinanceLeaseObligationsInHeldForSale_766f7f64-9783-40a4-84f0-8fa98769efd7" xlink:type="arc" order="32"/>
  </link:definitionLink>
</link:linkbase>
