城门一种构造，围绕着上述的出口或入口，比如一个山区或一设防的出口通向一宫殿或一有城墙的城市 The structure surrounding such an opening, such as the monumental or fortified entrance to a palace or walled city.
护城河一条深而宽的、通常有水沟环绕设防的中世纪城镇城堡或堡垒，用以抵抗外来袭击 A deep, wide ditch, usually filled with water, typically surrounding a fortified medieval town, fortress, or castle as a protection against assault.
卫城古希腊城市的设防的城堡或要塞 The fortified height or citadel of an ancient Greek city.
城堡带有厚墙的用来设防的大型建筑物或建筑群，通常控制周围的村庄 A large fortified building or group of buildings with thick walls, usually dominating the surrounding country.
