Architectural highlight (5)
I believe the answer is:
oriel
'architectural highlight' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for oriel that I've seen before include "corbelled window?" , "Projecting bay window -- Oxford college" , "Window built out from upper floor" , "Upper-story bay window" , "Upstairs bay window" .)