auxiliary (adj./n.) (aux, AUX)

A term used in the GRAMMATICAL classification of VERBS to refer to the set of verbs, subordinate to the main LEXICAL verb, which help to make distinctions in MOOD, ASPECT, VOICE, etc.; also called auxiliary verbs. In English the main auxiliaries are do, be and have, e.g. she is leaving, does she know, she has taken. The MODAL auxiliaries include can/ could, may/might, shall/should, will/would, must, ought to and used to. The class of auxiliaries is distinguished grammatically from lexical verbs in several ways; for instance, they have a special NEGATIVE form (e.g. isn’t, hasn’t, can’t, as opposed to *walkn’t), and they can be used with SUBJECT INVERSION (e.g. is he, does he, will they, as opposd to *walks he). ‘Marginal’ or ‘semi-auxiliaries’, i.e. verbs which display some but not all of the properties of the auxiliary class, include dare and need.