An
auxiliary verb is a
verb that adds functional or grammatical meaning to the
clause in which it appears—for example, to express
tense,
aspect,
modality,
voice, emphasis, etc. Auxiliary verbs usually accompany a main verb. The main verb provides the main semantic content of the clause. An example is the verb
have in the sentence
I have finished my dinner. Here, the main verb is
finish, and the auxiliary
have helps to express the
perfect aspect. Some sentences contain a chain of two or more auxiliary verbs. Auxiliary verbs are also called
helping verbs,
helper verbs, or
(verbal) auxiliaries. They may be
glossed with the abbreviation
AUX.