Musical transition (5)
I believe the answer is:
segue
'musical transition' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for segue that I've seen before include "Follow smoothly on" , "Move between songs, etc, without a pause" , "Follow on without a pause" , "In music, an immediate transition from one part to another" , "Change smoothly from one thing to another" .)