College window (5)
I believe the answer is:
oriel
This clue is a double definition.
'college' is the first definition.
(Oxford University college)
'window' is the second definition.
(oriel is a type of window)
(Other definitions for oriel that I've seen before include "Form of bay window" , "Loire (anag.)" , "First-floor bay (window)" , "Recessed bay window" , "Oxford college, founded 1326" .)