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.-the upper voice in part music.-the canto, cantus, or soprano voice; the treble.-a discourse formed on its theme, like variations on a musical air; a comment or comments.-to sing a variation or accomplishment.-to comment freely; to discourse with fullness and particularity; to discourse at large.