Fight sites
I believe the answer is:
arenas
'fight sites' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for arenas that I've seen before include "Areas in centre of amphitheatres" , "Central areas of, say, sports stadiums" , "rings" , "Areas for events, sports perhaps" , "Areas for events, sporting perhaps" .)