modal auxiliary

noun

: an auxiliary verb (such as can, must, might, may) that is characteristically used with a verb of predication and expresses a modal modification and that in English differs formally from other verbs in lacking -s and -ing forms

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What is a modal verb?

A small group of auxiliary verbs, called the modal verbs (or modal auxiliary verbs, modal auxiliaries, or simply modals) are only used in combination with ordinary verbs. A modal verb changes the other verb's meaning to something different from simple fact. Modals may express permission, ability, prediction, possibility, or necessity.

The principal modal verbs are: can, could, may, might, must, ought, shall, should, will, and would.

The modal verbs are different from ordinary verbs in several ways: 1) they have no inflections at all; that is, they lack an -ing form, an -ed form, and even an -s form for the third-person singular; 2) a modal verb is always followed by the infinitive form of a verb (unless that verb has already been stated) but never follows another verb; 3) modal verbs do not follow to and are not followed by to. (Ought to, like the near-modal verb have to, is a special case.)

In their simple form, modal verbs normally refer to present or future time:

I must be nearly there by now.

I might arrive a bit later than I'd anticipated.

A trip like this can take hours more than one expects.

Word History

First Known Use

circa 1904, in the meaning defined above

Time Traveler
The first known use of modal auxiliary was circa 1904

Dictionary Entries Near modal auxiliary

Cite this Entry

“Modal auxiliary.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/modal%20auxiliary. Accessed 27 Nov. 2022.

Kids Definition

modal auxiliary

noun

: a verb (as can, must, might, should) that is typically used with another verb to indicate that the state or action expressed is something other than a simple fact (as a possibility or a necessity)
in "we may go tomorrow" "may" is a modal auxiliary
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