copula (n.)

A term used in GRAMMATICAL description to refer to a linking VERB, i.e. a verb which has little independent MEANING, and whose main function is to relate other elements of CLAUSE structure, especially SUBJECT and COMPLEMENT. In English, the main copular (or copulative) verb is be, e.g. She is a doctor, and the term is often restricted to this verb; but there are many others which have a similar function, e.g. She feels angry, That looks nice, He fell ill.