Pointed arch (5)
I believe the answer is:
ogive
'pointed arch' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ogive that I've seen before include "Gothic window" , "Pointed arch; diagonal rib of vault (architecture)" , "Lancet arch" , "high-level support" , "Pointed or Gothic arch" .)