The Collaborative International Dictionary of English v.0.48:

Sentry \Sen"try\, n.; pl. Sentires. [Probably from OF.
   senteret a little patch; cf. F. sentier path, and OF. sente.
   See Sentinel.]
   1. (Mil.) A soldier placed on guard; a sentinel.
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   2. Guard; watch, as by a sentinel.
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            Here toils, and death, and death's half-brother,
            sleep,
            Forms terrible to view, their sentry keep. --Dryden.
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   Sentry box, a small house or box to cover a sentinel at his
      post, and shelter him from the weather.
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The Collaborative International Dictionary of English v.0.48:

Kite \Kite\ (k[imac]t), n. [OE. kyte, AS. c[=y]ta; cf. W. cud,
   cut.]
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   1. (Zool.) Any raptorial bird of the subfamily Milvin[ae],
      of which many species are known. They have long wings,
      adapted for soaring, and usually a forked tail.
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   Note: The European species are Milvus ictinus and Milvus
         migrans; the pariah kite of India is Milvus govinda;
         the sacred or Brahmany kite of India is Haliastur
         Indus; the American fork-tailed kite is the Nauclerus
         furcatus.
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   2. Fig.: One who is rapacious.
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            Detested kite, thou liest.            --Shak.
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   3. A light frame of wood or other material covered with paper
      or cloth, for flying in the air at the end of a string.
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   4. (Naut.) A lofty sail, carried only when the wind is light.
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   5. (Geom.) A quadrilateral, one of whose diagonals is an axis
      of symmetry. --Henrici.
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   6. Fictitious commercial paper used for raising money or to
      sustain credit, as a check which represents no deposit in
      bank, or a bill of exchange not sanctioned by sale of
      goods; an accommodation check or bill. [Cant]
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   7. (Zool.) The brill. [Prov. Eng.]
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   8. (Naut.) A form of drag to be towed under water at any
      depth up to about forty fathoms, which on striking bottom
      is upset and rises to the surface; -- called also
      sentry.
      [Webster 1913 Suppl.]

   Flying kites. (Naut.) See under Flying.

   Kite falcon (Zool.), an African falcon of the genus
      Avicida, having some resemblance to a kite.
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WordNet (r) 3.0 (2006):

sentry
    n 1: a person employed to keep watch for some anticipated event
         [syn: lookout, lookout man, sentinel, sentry,
         watch, spotter, scout, picket]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "sentry":
   Argus, Cassandra, Charley, Jeremiah, admonisher, airplane spotter,
   cautioner, fire patrolman, fire warden, fireguard, flagman,
   forward observer, lighthouse keeper, lookout, lookout man, monitor,
   night watchman, patrol, patroller, patrolman, picket,
   prophet of doom, roundsman, scout, sentinel, signaler, signalman,
   spotter, vedette, ward, warner, watch, watcher, watchkeeper,
   watchman