a soldier whose job is to guard something synonym sentry哨兵 - (figurative)
a tall round tower standing sentinel over the river 鎮守在河邊的一座高高的圓塔 Large dark pines stood like sentinels guarding the wintry garden. 巨大的黑鬆像哨兵一樣守衛着冬天的花園。
Word Originlate 16th cent.: from French sentinelle, from Italian sentinella, of unknown origin.- (figurative)