diff --git a/EventOntology.ttl b/EventOntology.ttl
index fa2d4a9..4884350 100644
--- a/EventOntology.ttl
+++ b/EventOntology.ttl
@@ -2056,7 +2056,8 @@ cco:LossOfSpecificallyDependentContinuant rdf:type owl:Class ;
 ###  http://www.ontologyrepository.com/CommonCoreOntologies/Loudness
 cco:Loudness rdf:type owl:Class ;
              rdfs:subClassOf cco:SoundProcessProfile ;
-             cco:definition "A Sound Process Profile that is characterized by the amplitude, frequency and power of translated sound waves, typically on a continuum from soft to loud."@en ;
+             cco:definition "A Sound Process Profile that is characterized by the amplitude and total energy of translated sound waves, typically on a continuum from soft to loud."@en ;
+             cco:definition_source "https://byjus.com/physics/loudness-of-sound/"^^xsd:anyURI ;
              cco:is_curated_in_ontology "http://www.ontologyrepository.com/CommonCoreOntologies/Mid/EventOntology"^^xsd:anyURI ;
              rdfs:label "Loudness"@en .