diff --git a/src/cco-modules/AgentOntology.ttl b/src/cco-modules/AgentOntology.ttl
index 28010a9..de109df 100644
--- a/src/cco-modules/AgentOntology.ttl
+++ b/src/cco-modules/AgentOntology.ttl
@@ -1164,7 +1164,7 @@ cco:Agent rdf:type owl:Class ;
                                 rdf:type owl:Class
                               ] ;
           rdfs:subClassOf obo:BFO_0000040 ;
-          cco:definition "A Material Entity that bears an Agent Capability."@en ;
+          skos:definition "A Material Entity that bears an Agent Capability."@en ;
           cco:definition_source "Schlosser, Markus, \"Agency\", The Stanford Encyclopedia of Philosophy (Winter 2019 Edition), Edward N. Zalta (ed.), available at: https://plato.stanford.edu/archives/win2019/entries/agency/"@en ;
           cco:is_curated_in_ontology "http://www.ontologyrepository.com/CommonCoreOntologies/Mid/AgentOntology"^^xsd:anyURI ;
           rdfs:label "Agent"@en .
@@ -1173,7 +1173,7 @@ cco:Agent rdf:type owl:Class ;
 ###  http://www.ontologyrepository.com/CommonCoreOntologies/AgentCapability
 cco:AgentCapability rdf:type owl:Class ;
                     rdfs:subClassOf obo:BFO_0000017 ;
-                    cco:definition "A Realizable Entity that inheres in a Material Entity to the extent of that Material Entity's capacity to realize it in Planned Acts of a certain type."@en ;
+                    skos:definition "A Realizable Entity that inheres in a Material Entity to the extent of that Material Entity's capacity to realize it in Planned Acts of a certain type."@en ;
                     cco:definition_source "Schlosser, Markus, \"Agency\", The Stanford Encyclopedia of Philosophy (Winter 2019 Edition), Edward N. Zalta (ed.), available at: https://plato.stanford.edu/archives/win2019/entries/agency/"@en ;
                     cco:is_curated_in_ontology "http://www.ontologyrepository.com/CommonCoreOntologies/Mid/AgentOntology"^^xsd:anyURI ;
                     rdfs:label "Agent Capability"@en .