<?xml version="1.0" encoding="UTF-8"?><!-- Generated by Broadridge Financial Solutions Inc --><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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt"  xmlns:macquarie="http://macquarie/20260731">
			<link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ProspectusOnly" roleURI="http://xbrl.sec.gov/rr/role/ProspectusOnly"/>
			<link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#SeriesOnly" roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly"/>
			<link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#ClassOnly" roleURI="http://xbrl.sec.gov/oef/role/ClassOnly"/>
			<link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#RiskOnly" roleURI="http://xbrl.sec.gov/rr/role/RiskOnly"/>
			<link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#PerformanceMeasureOnly" roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly"/>
			<link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default"/>
			<link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain"/>
			<link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension"/>
			<link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member"/>
			<link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all"/>
		<link:definitionLink xlink:role="http://xbrl.sec.gov/rr/role/ProspectusOnly" xlink:type="extended"><link:loc xlink:type="locator" xlink:label="DocumentDomain" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_DocumentDomain"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_Djulycombopro_2793Member" xlink:label="Djulycombopro_2793Member" /><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DocumentDomain" xlink:to="Djulycombopro_2793Member" use="optional" order="1.0"/></link:definitionLink><link:definitionLink xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:type="extended"><link:loc xlink:type="locator" xlink:label="dei_EntityDomain" xlink:href="https://xbrl.sec.gov/dei/2026/dei-2026.xsd#dei_EntityDomain"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_S000018873Member" xlink:label="S000018873Member" /><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="dei_EntityDomain" xlink:to="S000018873Member" use="optional" order="2.0"/></link:definitionLink><link:definitionLink xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="extended"><link:loc xlink:type="locator" xlink:label="ShareClassDomain" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_ShareClassDomain"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_C000052257Member"  xlink:label="C000052257Member"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_C000052258Member"  xlink:label="C000052258Member"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_C000052259Member"  xlink:label="C000052259Member"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_C000052260Member"  xlink:label="C000052260Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain"  use="optional" xlink:to="C000052257Member" order="2" /><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain"  use="optional" xlink:to="C000052258Member" order="3" /><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain"  use="optional" xlink:to="C000052259Member" order="4" /><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain"  use="optional" xlink:to="C000052260Member" order="5" /></link:definitionLink><link:definitionLink xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" xlink:type="extended"><link:loc xlink:type="locator" xlink:label="PerformanceMeasureDomain" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_PerformanceMeasureDomain"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260421233Member" xlink:label="bench20260421233Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain"  use="optional" xlink:to="bench20260421233Member" order="410.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260727285Member" xlink:label="bench20260727285Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain"  use="optional" xlink:to="bench20260727285Member" order="413.0" /></link:definitionLink><link:definitionLink xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:type="extended"><link:loc xlink:type="locator" xlink:label="oef_AllRisksMember" xlink:href="https://xbrl.sec.gov/oef/2026/oef-2026.xsd#oef_AllRisksMember"/><link:loc xlink:type="locator" xlink:label="us-gaap_FixedIncomeSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FixedIncomeSecuritiesMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_FixedIncomeSecuritiesMember" order="11" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:label="us-gaap_MortgageBackedSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MortgageBackedSecuritiesMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_MortgageBackedSecuritiesMember" order="15" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:label="us-gaap_CollateralizedMortgageObligationsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CollateralizedMortgageObligationsMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_CollateralizedMortgageObligationsMember" order="16" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:label="us-gaap_CommercialMortgageBackedSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialMortgageBackedSecuritiesMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_CommercialMortgageBackedSecuritiesMember" order="18" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:label="us-gaap_AssetBackedSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetBackedSecuritiesMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_AssetBackedSecuritiesMember" order="20" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:label="us-gaap_SovereignDebtSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SovereignDebtSecuritiesMember"/><link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember" xlink:to="us-gaap_SovereignDebtSecuritiesMember" order="25" xbrldt:closed="true"/><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench2025112098Member" xlink:label="bench2025112098Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench2025112098Member" order="44.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20251218133Member" xlink:label="bench20251218133Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20251218133Member" order="45.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260126137Member" xlink:label="bench20260126137Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20260126137Member" order="46.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260706253Member" xlink:label="bench20260706253Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20260706253Member" order="47.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260421213Member" xlink:label="bench20260421213Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20260421213Member" order="48.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260706257Member" xlink:label="bench20260706257Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20260706257Member" order="49.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20260421223Member" xlink:label="bench20260421223Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20260421223Member" order="410.0" /><link:loc xlink:type="locator" xlink:href="macquarie-20260731.xsd#macquarie_bench20251120103Member" xlink:label="bench20251120103Member"/><link:definitionArc  xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="oef_AllRisksMember"  use="optional" xlink:to="bench20251120103Member" order="411.0" /></link:definitionLink></link:linkbase>