ˌdiː.noʊˈteɪ.ʃən ɪkˈstɛnʃən ɪndɪˈkeɪʃən ˈɹɛf.(ə)ɹəns 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 the act of indicating or pointing out by name