1. the act of indicating or pointing out by name • Syn: indication • Derivationally related forms: denote, indicate (for: indication) • Hypernyms: naming 2. the most direct or specific meaning of a word or expression; the class of objects that an expression refers to - the extension of 'satellite of Mars' is the set containing only Demos and Phobos • Syn: reference, extension • Derivationally related forms: extensional (for: extension), denote, referent (for: reference), refer (for: reference) • Hypernyms: meaning, substance