Webster's Revised Unabridged Dictionary · 1913

Monophonic

Monophonic , adjective

[Mono- + Greek {not transcribed} a voice.]

1.
(Music) Single-voiced; having but one part; as, a monophonic composition; -- opposed to polyphonic.
2.
Of or relating to a system for recording and reproducing sound, which has only one sound channel; also called monaural or mono. It contrasts with stereophonic (or stereo), quadraphonic, or surround-sound, which have two or more channels, and can thus reproduce the effect of the sound coming from more than one direction.