monophonic

a. [ Mono- + Gr. &unr_; a voice. ] 1. (Mus.) Single-voiced; having but one part; as, a monophonic composition; -- opposed to polyphonic. [ 1913 Webster ]

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. [ PJC ]