Musical form with a recurring theme (5)
I believe the answer is:
rondo
'musical form with a recurring theme' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rondo that I've seen before include "Musical form with recurrent theme" , "Repetitive musical form" , "Piece written" , "Piece of music with repeated refrain" , "Repetitive movement" .)