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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019fccc1-51bd-723f-ab33-c5b23c23c00a,g:1aa2dc03-10a8-41b8-86ef-067d7a7fb801-->
<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://fhlb.com/role/Cover" xlink:type="simple" xlink:href="fhlbd-20260729.xsd#Cover"/>
  <link:definitionLink xlink:role="http://fhlb.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitiesTable_019fccc1-51bd-79ce-9f5c-3e66dd280934" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntitiesTable_019fccc1-51bd-79ce-9f5c-3e66dd280934" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_019fccc1-51bd-71ec-9b89-0458b71117f0" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_dei_EntitiesTable_019fccc1-51bd-79ce-9f5c-3e66dd280934" xlink:to="loc_dei_LegalEntityAxis_019fccc1-51bd-71ec-9b89-0458b71117f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fccc1-51bd-71ec-9b89-0458b71117f0_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_019fccc1-51bd-71ec-9b89-0458b71117f0" xlink:to="loc_dei_EntityDomain_019fccc1-51bd-71ec-9b89-0458b71117f0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_019fccc1-51bd-772d-9fe3-45c90867074c" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_019fccc1-51bd-71ec-9b89-0458b71117f0" xlink:to="loc_dei_EntityDomain_019fccc1-51bd-772d-9fe3-45c90867074c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_019fccc1-51bd-739f-addc-b24072c1f12b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_AmendmentFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_AmendmentFlag_019fccc1-51bd-739f-addc-b24072c1f12b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_019fccc1-51bd-7e42-a7f9-f264d1828531" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentType"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_DocumentType_019fccc1-51bd-7e42-a7f9-f264d1828531" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_019fccc1-51bd-724c-b2c6-dd3ebc6d7fe4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_DocumentPeriodEndDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_DocumentPeriodEndDate_019fccc1-51bd-724c-b2c6-dd3ebc6d7fe4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_019fccc1-51bd-711a-98f7-6c5fe0267e42" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityRegistrantName"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityRegistrantName_019fccc1-51bd-711a-98f7-6c5fe0267e42" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_019fccc1-51bd-7694-b611-cc6eed4f53e0" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityCentralIndexKey"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityCentralIndexKey_019fccc1-51bd-7694-b611-cc6eed4f53e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_019fccc1-51bd-7281-aa9e-0f21991c2ebf" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityFileNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityFileNumber_019fccc1-51bd-7281-aa9e-0f21991c2ebf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_019fccc1-51bd-7c10-870f-d024b35847e1" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityTaxIdentificationNumber_019fccc1-51bd-7c10-870f-d024b35847e1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_019fccc1-51bd-7b29-804f-9a62902bb547" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressAddressLine1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityAddressAddressLine1_019fccc1-51bd-7b29-804f-9a62902bb547" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_019fccc1-51bd-7c11-9641-14be0757a6f2" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressCityOrTown"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityAddressCityOrTown_019fccc1-51bd-7c11-9641-14be0757a6f2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_019fccc1-51bd-7dde-856d-f2dcd52dea89" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressStateOrProvince"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityAddressStateOrProvince_019fccc1-51bd-7dde-856d-f2dcd52dea89" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_019fccc1-51bd-7425-80b1-db59b4a5237c" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityAddressPostalZipCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityAddressPostalZipCode_019fccc1-51bd-7425-80b1-db59b4a5237c" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_019fccc1-51bd-79e4-88cc-c1feb1bbac51" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_CityAreaCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_CityAreaCode_019fccc1-51bd-79e4-88cc-c1feb1bbac51" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_019fccc1-51bd-7588-831c-fb093b863b05" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LocalPhoneNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_LocalPhoneNumber_019fccc1-51bd-7588-831c-fb093b863b05" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_WrittenCommunications_019fccc1-51bd-7245-b70e-37c845f2cfdc" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_WrittenCommunications"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_WrittenCommunications_019fccc1-51bd-7245-b70e-37c845f2cfdc" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SolicitingMaterial_019fccc1-51bd-78d8-b1dd-f99ead98ee19" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_SolicitingMaterial"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_SolicitingMaterial_019fccc1-51bd-78d8-b1dd-f99ead98ee19" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementTenderOffer_019fccc1-51bd-7855-8c44-2cf1bcdb5362" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_PreCommencementTenderOffer_019fccc1-51bd-7855-8c44-2cf1bcdb5362" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_PreCommencementIssuerTenderOffer_019fccc1-51bd-733b-9d97-dc066e771553" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_PreCommencementIssuerTenderOffer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_PreCommencementIssuerTenderOffer_019fccc1-51bd-733b-9d97-dc066e771553" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_019fccc1-51bd-7f12-86f8-59f182ea507b" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityEmergingGrowthCompany_019fccc1-51bd-7f12-86f8-59f182ea507b" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_019fccc1-51bd-7a4d-bbe1-bd5585529787" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityInformationLineItems_019fccc1-51bd-7f5b-8f32-afc875eab0ed" xlink:to="loc_dei_EntityIncorporationStateCountryCode_019fccc1-51bd-7a4d-bbe1-bd5585529787" xlink:type="arc" order="18"/>
  </link:definitionLink>
</link:linkbase>
