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 long mound of earth, stone, or similar material, usually built for purposes such as to hold back or store water, for protection from weather or enemies, or to support a road or railway.