diff --git a/ArtifactOntology.ttl b/ArtifactOntology.ttl
index 5ea898f..ad7fe9e 100644
--- a/ArtifactOntology.ttl
+++ b/ArtifactOntology.ttl
@@ -1665,7 +1665,7 @@ cco:FrictionReductionArtifactFunction rdf:type owl:Class ;
 ###  http://www.ontologyrepository.com/CommonCoreOntologies/FuelArtifactFunction
 cco:FuelArtifactFunction rdf:type owl:Class ;
                          rdfs:subClassOf cco:ArtifactFunction ;
-                         cco:definition "An Artifact Function that is realized in processes in which an Artifact is reacted with other substances in order to release chemical or nuclear energy to be used for heat or for work."@en ;
+                         cco:definition "An Artifact Function that is realized in processes in which a Portion of Fuel is reacted with other substances in order to release chemical or nuclear energy to be used for heat or for work."@en ;
                          cco:definition_source "https://en.wikipedia.org/w/index.php?title=Fuel&oldid=1063590518"^^xsd:anyURI ;
                          cco:is_curated_in_ontology "http://www.ontologyrepository.com/CommonCoreOntologies/Mid/ArtifactOntology"^^xsd:anyURI ;
                          rdfs:label "Fuel Artifact Function"@en .
@@ -3096,7 +3096,7 @@ cco:PortionOfFood rdf:type owl:Class ;
 ###  http://www.ontologyrepository.com/CommonCoreOntologies/PortionOfFuel
 cco:PortionOfFuel rdf:type owl:Class ;
                   rdfs:subClassOf cco:PortionOfMaterial ;
-                  cco:definition "A Portion of Material that is designed to be used as an input in a Combustion process."@en ;
+                  cco:definition "A Portion of Material that is designed to release thermal energy when reacted with other substances."@en ;
                   cco:is_curated_in_ontology "http://www.ontologyrepository.com/CommonCoreOntologies/Mid/ArtifactOntology"^^xsd:anyURI ;
                   rdfs:label "Portion of Fuel"@en .