Projecting part of a fortification (7)
I believe the answer is:
bastion
'projecting part of a fortification' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for bastion that I've seen before include "Obtains (anag.)" , "part of stronghold" , "Projecting part of a fortification" , "Obtains in fortified place or stronghold" , "Stronghold, fortification" .)