(Mus.)
(a)
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.
(b)
The upper voice in part music.
(c)
The canto, cantus, or soprano voice; the treble. "Twenty doctors expound one text twenty ways, as children make descant upon plain song." "She (the nightingale) all night long her amorous descant sung." Note: The term has also been used synonymously with counterpoint, or polyphony, which developed out of the French déchant, of the 12th century.