Circle of musicians (4)
I believe the answer is:
band
I believe this is a double definition.
'circle' is the first definition.
('band' can be a synonym of 'circle')
'musicians' is the second definition.
(I've seen this before)
'of' acts as a link.
(Other definitions for band that I've seen before include "Body" , "Ring or musical group (4)" , "company" , "Pop group; stripe" , "Belt; group of musicians" .)