Florid organum

(Aquitainian or melismatic organum) A twelfth-century polyphonic composition based on plainchant in which a new ornate voice is added above the original voice, moving faster than the original plainchant line. (The notation does not specify rhythms, however.) A mixture of intervals appears, though cadences fall on perfect intervals (unisons, fourths, fifths, and octaves). See organum.