diff --git a/ontology/saref4wear.ttl b/ontology/saref4wear.ttl
index fa3273bd39d6e21a2fabaa064bd6202583d786be..676a84b2dfd81fa57abe560b1057542e3205b790 100644
--- a/ontology/saref4wear.ttl
+++ b/ontology/saref4wear.ttl
@@ -157,17 +157,17 @@ s4wear:Device rdf:type owl:Class .
 
 ###  https://saref.etsi.org/s4wear#LivingOrganism
 s4wear:LivingOrganism rdf:type owl:Class ;
-                      rdfs:subClassOf s4wear:Wearer .
+                      rdfs:subClassOf :Entity .
 
 
 ###  https://saref.etsi.org/s4wear#PhysicalObject
 s4wear:PhysicalObject rdf:type owl:Class ;
-                      rdfs:subClassOf s4wear:Wearer .
+                      rdfs:subClassOf :Entity .
 
 
 ###  https://saref.etsi.org/s4wear#Software
 s4wear:Software rdf:type owl:Class ;
-                rdfs:subClassOf s4wear:Wearer .
+                rdfs:subClassOf :Entity .
 
 
 ###  https://saref.etsi.org/s4wear#Wearable
@@ -180,6 +180,14 @@ The definition of this concept satisfies the requirement WEAR-1."""@en ;
 
 ###  https://saref.etsi.org/s4wear#Wearer
 s4wear:Wearer rdf:type owl:Class ;
+              rdfs:subClassOf [ owl:intersectionOf ( :Entity
+                                                     [ rdf:type owl:Restriction ;
+                                                       owl:onProperty s4wear:isSensedBy ;
+                                                       owl:someValuesFrom s4wear:Wearable
+                                                     ]
+                                                   ) ;
+                                rdf:type owl:Class
+                              ] ;
               rdfs:comment """A wearer is any living organism that is sensed by a wearable.
 The definition of this concept satisfies the requirement WEAR-2."""@en ;
               rdfs:label "Wearer"@en .
@@ -214,6 +222,10 @@ The definition of this concept satisfies the requirement WEAR-2."""@en ;
           rdfs:subClassOf :Information .
 
 
+###  https://saref.etsi.org/saref4wear#Entity
+:Entity rdf:type owl:Class .
+
+
 ###  https://saref.etsi.org/saref4wear#Fabric
 :Fabric rdf:type owl:Class ;
         rdfs:subClassOf :TextileBasedWearable .
@@ -290,7 +302,15 @@ The definition of this concept satisfies the requirement WEAR-2."""@en ;
 
 
 ###  https://saref.etsi.org/saref4wear#User
-:User rdf:type owl:Class .
+:User rdf:type owl:Class ;
+      rdfs:subClassOf [ owl:intersectionOf ( :Entity
+                                             [ rdf:type owl:Restriction ;
+                                               owl:onProperty :interactsWith ;
+                                               owl:someValuesFrom s4wear:Wearable
+                                             ]
+                                           ) ;
+                        rdf:type owl:Class
+                      ] .
 
 
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