Large defensive structure (8)

I believe the answer is:
fortress
(Other definitions for fortress that I've seen before include "Place that's secure" , "Castle" , "it's hard to break into" , "Secure building" , "Strong point" .)
I believe the answer is:
fortress
(Other definitions for fortress that I've seen before include "Place that's secure" , "Castle" , "it's hard to break into" , "Secure building" , "Strong point" .)