Central courtyards (5)
I believe the answer is:
atria
'central courtyards' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for atria that I've seen before include "Lobbies" , "Central courts (in ancient Rome or shopping arcades)" , "Central areas in buildings; open to the sky" , "entrances" , "Open-roofed courts" .)