fortress
n. 堡垒；要塞
vt. 筑要塞；以要塞防守
复数 fortresses
例句
Fear of terrorist attack has turned the conference centre into a fortress.
由于害怕恐怖分子袭击，会议中心已变成了堡垒。
《牛津词典》
It's easier to "capture the fortress from within."
堡垒更容易从内部攻破。
《新英汉大辞典》
The general hastened to the relief of the fortress.
将军火速前往救援该要塞。
