Monophonic

1. (Mus.) 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.