cantus firmuscan·tus fir·mus
an existing melody used as the basis for a new polyphonic composition
Origin of cantus firmusML, literally , fixed song
A preexisting melody used as the basis of a polyphonic composition, especially in polyphony of the 1300s and 1400s.
Origin of cantus firmusMedieval Latin : Latin cantus, song + Latin firmus, fixed.
(plural cantus firmi)