a soldier whose job is to guard something 哨兵 to be on sentry duty 放哨 People approaching the gate were challenged by the sentry. 接近门口的人受到哨兵的盘查。 Everyone took their turn at sentry duty. 每个人都轮流担任哨兵。
Oxford Collocations DictionarySentry is used before these nouns:- duty
Word Originearly 17th cent.: perhaps from obsolete centrinel, variant of sentinel.