A place of safety or refuge.
The protection, physical and legal, afforded by such a place (as, for example, for political refugees).
A defense or safeguard.
A defensive wall or rampart.
A breakwater.
Any means of defence or security.
The planking or plating along the sides of a nautical vessel above her gunwale that reduces the likelihood of seas washing over the gunwales and people being washed overboard.
To fortify something with a wall or rampart.
To provide protection of defense for something.