Discantus

A 12th- to 15th-century term for certain types of polyphonic music in which a part was composed against the plainsong, or in some cases perhaps improvised. In distinguishing discant from organum, the former designates two-voice polyphony in note-against-note style, the latter a more elaborate setting employing (or at least including) melismas in the upper part. Perotin was skilled in the art of discant, being described as "optimus discantor," while Leonin was called "optimus organista."

The term "discant" originated as a designation for the upper voice only, the lower part being called "cantus" ("cantus" = voice; "discantus" = second, or counter, voice). It came to denote the style used in the so-called discant sections of the organa of Notre Dame and in the two types of polyphony that originated from these, the clausula and motet. Stylistically, the conductus also belongs to the category of discant. Its opposite is the "organal" sections, in which the upper part moves in long melismas above a few sustained notes of the tenor.