I. ˌmodal ˈverb (also modal) noun [countable] technical
one of these verb forms: can, could, may, might, shall, should, will, would, must, ought to, used to, need, had better, and dare. They are all used with other verbs to express ideas such as possibility, permission, or intention ⇒ auxiliary verb

[TahlilGaran] Dictionary of Contemporary English ▲

II. mo‧dal¹ /ˈməʊdl $ ˈmoʊdl/ noun [countable]
a modal verb

[TahlilGaran] Dictionary of Contemporary English ▲

III. modal² adjective technical
[Date: 1500-1600; Language: Medieval Latin; Origin: modalis, from Latin modus; ⇒ mode]

1. [only before noun] modal meanings are concerned with the attitude of the speaker to the hearer or to what is being said

2. related to or written in a musical mode(5)
—modality /məʊˈdæləti, məʊˈdælɪti $ moʊ-/ noun [uncountable]

[TahlilGaran] Dictionary of Contemporary English ▲