Protective castle wall (7)
I believe the answer is:
parapet
(Other definitions for parapet that I've seen before include "Wall's top" , "part of castle" , "Protective cover" , "balustrade" , "protection from fire" .)
I believe the answer is:
parapet
(Other definitions for parapet that I've seen before include "Wall's top" , "part of castle" , "Protective cover" , "balustrade" , "protection from fire" .)