auxiliary verb

noun
1.
a word used in construction with and preceding certain forms of other verbs, as infinitives or participles, to express distinctions of tense, aspect, mood, etc., as did in Did you go?, am in I am listening, have in We have spoken, or can in They can see.
Also called helping verb.
Origin
1755-65
British Dictionary definitions for auxiliary verb

auxiliary verb

noun
1.
a verb used to indicate the tense, voice, mood, etc, of another verb where this is not indicated by inflection, such as English will in he will go, was in he was eating and he was eaten, do in I do like you, etc
auxiliary verb in Culture

auxiliary verb definition


A “helping” verb that modifies the main verb, as in “Gail can win,” “Gail did win,” “Gail could have won.” A question often begins with an auxiliary verb: “Did Gail win?” “Could Gail lose?” The various forms of the verbs can, have, is, and does frequently act as auxiliaries.