House could be Roman (5)
I believe the answer is:
manor
'house' is the definition.
(manor is a kind of house)
'could be roman' is the wordplay.
'could be' indicates an anagram.
'roman' anagrammed gives 'MANOR'.
(Other definitions for manor that I've seen before include "house on estate" , "police area" , "patch" , "Large country house for Roman" , "Big house - police district" .)