Complex sentence: In music, polyphony is a texture consisting of two or more simultaneous lines of independent melody, as opposed to music with just one voice (monophony) or music with one dominant melodic voice accompanied by chords (homophony).
Split into simpler sentences: In music, polyphony is a texture consisting of two or more simultaneous lines of independent melody, as opposed to music with just one voice, (monophony). Music with one dominant melodic voice accompanied by chords is called (homophony).