monophonic (adj.)youdaoicibaDictYouDict[monophonic 词源字典]
of recordings, broadcasts, etc., "not stereo, having only one output signal," 1958, coined to be an opposite of stereophonic; from mono- + -phonic, from Greek phone "sound, voice," from PIE root *bha- (2) "to speak, tell, say" (see fame (n.)).[monophonic etymology, monophonic origin, 英语词源]