Diaphonia

DIAPHONIA (from δις, twice; and (Φωνεω, I sound. Lat. Discantus; from dis, twice, and cantus, a song. Inexact synonym, Organum). A term, applied, by Guido d'Arezzo, in his Micrologus, to a form of composition in which a second Part, called Organum, was added below a given Cantus firmus. Writers, of somewhat later date, while generally describing Diaphonia under its Latinized name, Discantus, have treated that word as the exact synonym of Organum. Guido, however, clearly restricts the term, Organum,...