Dictionary
can•tus fir•mus
Pronunciation: (kan'tus fûr'mus), [key]1. the ancient traditional unisonal plainchant of the Christian Church, having its form set and its use prescribed by ecclesiastical tradition.
2. Music.a fixed melody to which other voices are added, typically in polyphonic treatment.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.