Descant

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.