1570s, from Middle French sentinelle (16c.), from Italian sentinella "a sentinel." OED says "No convincing etymology of the It. word has been proposed," but perhaps (via a notion of "perceive, watch"), from sentire "to hear," from Latin sentire "feel, perceive by the senses" (see sense (n.)).
实用例句
1. a tall round tower standing sentinel over the river
镇守在河边的一座高高的圆塔
来自《权威词典》
2. We gave the watchword, and the sentinel let us pass.
我们说出口令, 哨兵就把我们放过去了.
来自《现代汉英综合大词典》
3. The lone sentinel walked toward his post.
忧愁的哨兵走向岗哨.
来自《现代英汉综合大词典》
4. SENTINEL? Model 880 source projectors are portable, lightweight and compact industrial radiographic exposure devices.