ai

1.

ai, in old Lat., corresponding to ae: AIDILIS, CAISAR, AITERNOS, for Aedilis, Caesar, aeternus; also, still later, sometimes in the poets in the termination of the genitive of the first decl.; but, as in Enn. and Lucr., per diaeresin always dissyl. with long penult:

furit intus aquāï,

Verg. A. 7, 464:

aurāï simplicis ignem,

id. ib. 6, 747:

terrāï frugiferāï,

Mart. 11, 91, 5; cf. Quint. 1, 7, 18; Spauld. Prisc. 728; Prob. 1438; Vel. Long. 2222; Mart. Vict. 2460 P.—In prim. syllables, as in voc. Gaĭ, ăi could not be changed to ae if i was an ending; but i was changed to i cons., when the word received accession, e. g. Gaius. —When a conson. followed ai, as in CNAIVOS for GNAIWOS (v. the Epitaphs of the Scipios, in the Append.), ae was written at a later per., as Gnaeus; hence from Graïos both Graecus and Graius; from Aiakos, Aeacus, and Aiax, for Aias, were formed; just as Achaeus or Achivus with Achaĭus or Achaĭcus was used.

2.

* ai = ai, interj., denoting grief, ah! alas! Ov. M. 10, 215.

2.

ai, imper., from aio.