Fan \Fan\ (f[a^]n), n. [AS. fann, fr. L. vannus fan, van for
   winnowing grain; cf. F. van. Cf. Van a winnowing machine,
   Winnow.]
   1. An instrument used for producing artificial currents of
      air, by the wafting or revolving motion of a broad
      surface; as:
      (a) An instrument for cooling the person, made of
          feathers, paper, silk, etc., and often mounted on
          sticks all turning about the same pivot, so as when
          opened to radiate from the center and assume the
          figure of a section of a circle.
      (b) (Mach.) Any revolving vane or vanes used for producing
          currents of air, in winnowing grain, blowing a fire,
          ventilation, etc., or for checking rapid motion by the
          resistance of the air; a fan blower; a fan wheel.
      (c) An instrument for winnowing grain, by moving which the
          grain is tossed and agitated, and the chaff is
          separated and blown away.
      (d) Something in the form of a fan when spread, as a
          peacock's tail, a window, etc.
      (e) A small vane or sail, used to keep the large sails of
          a smock windmill always in the direction of the wind.
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                Clean provender, which hath been winnowed with
                the shovel and with the fan.      --Is. xxx. 24.
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   2. That which produces effects analogous to those of a fan,
      as in exciting a flame, etc.; that which inflames,
      heightens, or strengthens; as, it served as a fan to the
      flame of his passion.
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   3. A quintain; -- from its form. [Obs.] --Chaucer.
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   Fan blower, a wheel with vanes fixed on a rotating shaft
      inclosed in a case or chamber, to create a blast of air
      (fan blast) for forge purposes, or a current for draft and
      ventilation; a fanner.

   Fan cricket (Zool.), a mole cricket.

   Fan light (Arch.), a window over a door; -- so called from
      the semicircular form and radiating sash bars of those
      windows which are set in the circular heads of arched
      doorways.

   Fan shell (Zool.), any shell of the family Pectinid[ae].
      See Scallop, n., 1.

   Fan tracery (Arch.), the decorative tracery on the surface
      of fan vaulting.

   Fan vaulting (Arch.), an elaborate system of vaulting, in
      which the ribs diverge somewhat like the rays of a fan, as
      in Henry VII.'s chapel in Westminster Abbey. It is
      peculiar to English Gothic.

   Fan wheel, the wheel of a fan blower.

   Fan window. Same as Fan light (above).

   electric fan. a fan having revolving blades for propelling
      air, powered by an electric motor.
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