Discant

Discant (Latin: discantus, meaning "singing apart") was a style of liturgical setting in the Middle Ages, associated with the development of the Notre Dame school of polyphony. It is a style of organum that includes a plainchant tenor part, with a "note against note" upper voice, moving in contrary motion. It is not a musical form, but rather a technique. "English discant is three-voice parallelism in first-inversion triads."