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See also: Sentinel



1570s, from Middle French sentinelle, from Old Italian sentinella (perhaps via a notion of "perceive, watch", compare Italian sentire (to feel, hear, smell)), from Latin sentiō (feel, perceive by the senses). See sense.


  • (file)


sentinel (plural sentinels)

  1. A sentry or guard.
    • 1719- Daniel Defoe, Robinson Crusoe
      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 the entrance.
    • Macaulay
      the sentinels who paced the ramparts
  2. (computer science) a unique string of characters recognised by a computer program for processing in a special way; a keyword.
    The <xmp> tag is a sentinel that suspends web-page processing and displays the subsequent text literally.
  3. Watch; guard.
    • Francis Bacon
      that princes do keep due sentinel
  4. A sentinel crab.



sentinel (third-person singular simple present sentinels, present participle (US) sentineling or (UK) sentinelling, simple past and past participle (US) sentineled or (UK) sentinelled)

  1. (transitive) To watch over as a guard.
    He sentineled the north wall.
  2. (transitive) To post as guard.
    He sentineled him on the north wall.
  3. (transitive) To post a guard for.
    He sentineled the north wall with just one man.
    • 1873, Harper's New Monthly Magazine (volume 46, page 562)
      The old-fashioned stoop, with its suggestive benches on either side, lay solitary and silent in the moonlight; the garden path, weedily overgrown since father's death, and sentineled here and there with ragged hollyhock, lay quiet and dew-laden []