sentinels

Noun

sentinel (plural sentinels)

1. A sentry, watch, or guard.
   • They promised faithfully to bear their confinement with patience, and were very thankful that they had such good usage as to have provisions and light left them; for Friday gave them candles (such as we made ourselves) for their comfort; and they did not know but that he stood sentinel over them at...1719 May 6 (Gregorian calendar), [Daniel Defoe], The Life and Strange Surprizing Adventures of Robinson Crusoe, […], London: […] W[illiam] Taylor […], →OCLC
2. (obsolete) A private soldier.
   • “I will not permit the poorest centinel to be treated with injustice.”1789, John Moore, Zeluco, Valancourt, published 2008, page 33
3. A unique value recognised by a computer program for processing in a special way, or marking the end of a set of data.
   • The <xmp> tag is a sentinel that suspends web-page processing and displays the subsequent text literally
4. A sentinel crab.
5. (attributive) A sign of a health risk (e.g. a disease, an adverse effect).
   • sentinel animals can be used to explore endemic diseases.

See all 11 meanings of sentinel