The term was added to the ontology on the assumption it was a valid domain entity, but it turns out the entity does not exist in reality.

domain entity does not exist

This obsolesence reason should be used conservatively. For example: Obsoleting class that describes a breed of cow based on a record in an existing database, that was later retracted as faulty (breed does not exist). Do not use this term to obsolete a historic concept (that was once valid, but not anymore).