A relation between concepts and collections, where a Concept is said to characterize a Collection; it corresponds to a link between the (reified) intensional and extensional interpretations of a _proper subset of_ a (reified) class. This is different from covers, because it refers to an interpretation the entire reified class.
E.g. the collection of vintage saxophones is characterized by the Concept 'manufactured by hand', while it gets covered by the Concept 'Saxophone' with the Parameter 'Vintage'.