Twain (?), a. & n. [OE. twein, tweien, tweyne, AS. twēgen, masc. See Two.] Two;- nearly obsolete in common discourse, but used in poetry and burlesque. “Children twain.” Chaucer.
And whosoever shall compel thee to go a mile, go with him twain. Matt. v. 41.
In twain, in halves; into two parts; asunder.
When old winder split the rocks in twain. Dryden.
— Twain cloud. (Meteor.) Same as Cumulo-stratus.