Band in rush (4)
I believe the answer is:
belt
I believe this clue is a double definition.
'band' is the first definition.
(I've seen this before)
'rush' is the second definition.
(both can mean to run quickly)
'in' acts as a link.
(Other definitions for belt that I've seen before include "Zone; go quickly" , "Race" , "Zone; leather strip" , "Sign of rank in karate" , "Article of clothing" .)