(with lower-case 'm')
A style of composition in which all simultaneous 'lines' or voices have pitches which are in unison or 'octave' relationship. The impression is thus of one (mono) musical line, with no harmony.
Monophony is characteristic of the early-medieval European style of composition called plainchant (also called 'Gregorian chant', c. 500-1000 AD), and also of much of the world's folk music.
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