Projecting window (5)
I believe the answer is:
oriel
'projecting window' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oriel that I've seen before include "place to study at Oxford" , "Projecting window in upper storey" , "Opening" , "polygonal recess" , "Window built out from upper floor" .)