1. [syn: modal auxiliary verb, modal auxiliary, modal verb, modal]
The Collaborative International Dictionary of English v.0.48:
modal auxiliary \mo"dal aux*il"iar*y\(Gram.), n.
Any one of the auxiliary verbs of English, such as can, may,
will, shall, must, might, could, would, or should, which are
used together with the infinitive form of another verb to
express distinctions of mood, such as uncertainty,
possibility, command, emphasis, and obligation.
WordNet (r) 3.0 (2006):
n 1: an auxiliary verb (such as `can' or `will') that is used to
express modality [syn: modal auxiliary verb, modal
auxiliary, modal verb, modal]