A verb, such as have, can, or will, that accompanies the main verb in a clause and helps to make distinctions in mood, voice, aspect, and tense.
A verb used to help form the tenses, aspects, voices, or moods of other verbs, as will, have, do, be, should, must.
The definition of an auxiliary verb is used to change the tense or voice of other verbs.
An example of an auxiliary verb is "be", "do" or "have."
Attributive form of auxiliary verb, noun.