(1):

(v. i.) To comment freely; to discourse with fullness and particularity; to discourse at large.

(2):

(v. i.) A discourse formed on its theme, like variations on a musical air; a comment or comments.

(3):

(v. i.) To sing a variation or accomplishment.

(4):

(v. i.) Originally, a double song; a melody or counterpoint sung above the plain song of the tenor; a variation of an air; a variation by ornament of the main subject or plain song.

(5):

(v. i.) The upper voice in part music.

(6):

(v. i.) The canto, cantus, or soprano voice; the treble.