Cathedral area (4)
I believe the answer is:
apse
'cathedral area' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for apse that I've seen before include "Recess at east end of church" , "Church recess with domed or arched roof" , "place in church" , "inside church?" , "Rounded end of building" .)