Arm band (8)
I believe the answer is:
bracelet
'arm band' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bracelet that I've seen before include "Item of jewellery on wrist" , "Ornament - handcuff (slang)" , "Arm jewellery" , "Might Bel react badly to this jewellery?" , "Jewellery worn around the wrist" .)