(Gk.: ‘sounding apart’).
In ancient Greek theory, dissonance, as opposed to symphonia (consonance). In 9th-century music theory, however, the term was used synonymously with organum and symphonia to mean ‘polyphony in general’, and retained that general meaning until the 12th century, even though the symphoniae were still, specifically, the consonances of octave, 5th and 4th. During the 12th century ‘diaphonia’ was replaced by its Latin equivalent, ‘discantus’; ‘organum’ and ‘discantus’ then came to characterize different musical styles. Exceptionally, as late as 1321, Johannes de Muris (Ars novae musicae) used ‘diaphonia’ for organum, especially ‘diaphonia basilica’ for organum purum.
See also Discant, and Organum.
NICKY LOSSEFF