Music by The Stones? (4)

I believe the answer is:
rock
'music' is the definition.
(rock music)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rock that I've seen before include "Hard confectionery made in sticks" , "possible danger at sea" , "Perhaps Hudson" , "Move side to side" , "Sway to and fro - mass of stone" .)
