Long band of colour (6)
I believe the answer is:
stripe
'long band of colour' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stripe that I've seen before include "Military mark of rank, chevron" , "Sign of a soldier's rank" , "Braid showing military rank" , "Band of colour - 3 of rank" , "bar" .)