noun
castle wall; rampart; defensive wall
Refers to the thick outer walls of a castle or fortified town, often made of stone or earth. Can also be used for city walls in historical contexts.
その城の城壁は高さが10メートルもある。
The castle walls are as high as 10 meters.
中世の町は城壁に囲まれていた。
Medieval towns were surrounded by defensive walls.