A concept is that which is understood by a term, particularly a predicate. To possess a concept is to be able to deploy a term expressing it in making judgements: the ability connects with such things as recognizing when the term applies, and being able to understand the consequences of its application. The term ‘idea’ was formerly used in the same way, but is avoided because of its associations with subjective mental imagery, which may be irrelevant to the possession of a concept. In the semantics of Frege, a concept is the reference of a predicate, and cannot be referred to by a subject term. See also concept and object.