A temporary wooden tower built for defensive purposes.
An opening in the wall of a fortress through which the guns are levelled; a narrow loophole through which arrows and other missiles may be shot.
A tower at the entrance to a castle or fortified town
A fortress at the end of a bridge.
A defensive wall or rampart.
A defense or safeguard.
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.