Homophonous

Webster's Dictionary of the English Language

·adj Originally, sounding alike; of the same pitch; unisonous; monodic.

II. Homophonous ·adj Expressing the same sound by a different combination of letters; as, bay and bey.

III. Homophonous ·adj Now used for plain harmony, note against note, as opposed to polyphonic harmony, in which the several parts move independently, each with its own melody.