Musical counterpoint (7)
I believe the answer is:
descant
'musical counterpoint' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for descant that I've seen before include "Independent treble line" , "Highest range (eg of a 10)" , "Independent melody sung above a basic melody" , "Upper melody" , "Ornamental melody added above a theme" .)