Cool dance music genre (3-3)
I believe the answer is:
hip-hop
'music genre' is the definition.
'cool dance' is the wordplay.
'cool' becomes 'hip'.
'dance' becomes 'hop' (hop is a kind of dance).
'hip'+'hop'='HIP-HOP'
(Other definitions for hip-hop that I've seen before include "Electronic rap music" , "Popular music style" , "Genre of 1980s and '90s African-American music" , "Pop. music movement" .)