Eyelet (7)
I believe the answer is:
grommet
'eyelet' is the definition.
(I know that eyelet can be written as grommet)
This is all the clue.
(Other definitions for grommet that I've seen before include "Ring of rope or metal" , "Tube in eardrum to drain and ventilate ear" , "Eyelet lining a small hole" , "Metal ring for lining a small hole" , "insulation device" .)