diff --git a/ArtifactOntology.ttl b/ArtifactOntology.ttl
index 7445804..06c47e1 100644
--- a/ArtifactOntology.ttl
+++ b/ArtifactOntology.ttl
@@ -1675,7 +1675,7 @@ 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 of reacting with other substances in order to release chemical or nuclear energy as heat or ot be used 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 .
@@ -3106,7 +3106,7 @@ 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 .