Descant

1. A discourse formed on its theme, like variations on a musical air; a comment or comments.
2. 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.
3. The canto, cantus, or soprano voice; the treble.
4. The upper voice in part music.
5. To comment freely; to discourse with fullness and particularity; to discourse at large.
6. To sing a variation or accomplishment.