Gatherings of hair by a leader of fashion (6)
I believe the answer is:
flocks
'gatherings' is the definition.
(flock is a kind of gathering)
'hair by a leader of fashion' is the wordplay.
'hair' becomes 'locks' (I've seen this before**).
'by' is a charade indicator (letters next to each other).
'a leader of' says to take the initial letters.
The first letter of 'fashion' is 'f'.
'locks' after 'f' is 'FLOCKS'.
'of' acts as a link.
(Other definitions for flocks that I've seen before include "Tended by shepherds" , "Groups of animals" , "Groups of birds or sheep" .)