The Collaborative International Dictionary of English v.0.48:

Whistle \Whis"tle\, n. [AS. hwistle a pipe, flute, whistle. See
   Whistle, v. i.]
   [1913 Webster]
   1. A sharp, shrill, more or less musical sound, made by
      forcing the breath through a small orifice of the lips, or
      through or instrument which gives a similar sound; the
      sound used by a sportsman in calling his dogs; the shrill
      note of a bird; as, the sharp whistle of a boy, or of a
      boatswain's pipe; the blackbird's mellow whistle.
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            Might we but hear
            The folded flocks, penned in their wattled cotes, .
            . .
            Or whistle from the lodge.            --Milton.
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            The countryman could not forbear smiling, . . . and
            by that means lost his whistle.       --Spectator.
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            They fear his whistle, and forsake the seas.
                                                  --Dryden.
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   2. The shrill sound made by wind passing among trees or
      through crevices, or that made by bullet, or the like,
      passing rapidly through the air; the shrill noise (much
      used as a signal, etc.) made by steam or gas escaping
      through a small orifice, or impinging against the edge of
      a metallic bell or cup.
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   3. An instrument in which gas or steam forced into a cavity,
      or against a thin edge, produces a sound more or less like
      that made by one who whistles through the compressed lips;
      as, a child's whistle; a boatswain's whistle; a steam
      whistle (see Steam whistle, under Steam).
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            The bells she jingled, and the whistle blew. --Pope.
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   4. The mouth and throat; -- so called as being the organs of
      whistling. [Colloq.]
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            So was her jolly whistle well ywet.   --Chaucer.
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            Let's drink the other cup to wet our whistles.
                                                  --Walton.
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   Whistle duck (Zool.), the American golden-eye.
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