Monasteries (6)
I believe the answer is:
abbeys
'monasteries' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for abbeys that I've seen before include "Buildings occupied by monks or nuns" , "Buildings occupiedby communities of monks" , "Buildings occupied by communities of monks" , "Religious establishments" , "Places of worship f" .)