Sentence:  The independent <WSD>motions</WSD> of different parts sounding together constitute counterpoint. 
Meaning of the word marked with <WSD> tags:  Change of pitch in successive sounds, whether in the same part or in groups of parts. ("Conjunct motion" is that by single degrees of the scale. "Contrary motion" is when parts move in opposite directions. "Disjunct motion" is motion by skips. "Oblique motion" is when one part is stationary while another moves. "Similar" or "direct motion" is when parts move in the same direction.)