The Collaborative International Dictionary of English v.0.48:

Fan \Fan\, v. t. [imp. & p. p. Fanned; p. pr. & vb. n.
   Fanning.] [Cf. OF. vanner, L. vannere. See Fan, n., Van
   a winnowing machine.]
   1. To move as with a fan.
      [1913 Webster]

            The air . . . fanned with unnumbered plumes.
                                                  --Milton.
      [1913 Webster]

   2. To cool and refresh, by moving the air with a fan; to blow
      the air on the face of with a fan.
      [1913 Webster]

   3. To ventilate; to blow on; to affect by air put in motion.
      [1913 Webster]

            Calm as the breath which fans our eastern groves.
                                                  --Dryden.
      [1913 Webster]

   4. To winnow; to separate chaff from, and drive it away by a
      current of air; as, to fan wheat. --Jer. li. 2.
      [1913 Webster]

   5. To excite or stir up to activity, as a fan excites a
      flame; to stimulate; as, this conduct fanned the
      excitement of the populace.
      [1913 Webster]

   Fanning machine, or Fanning mill, a machine for
      separating seed from chaff, etc., by a blast of air; a
      fanner.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
          [1913 Webster]

                Clean provender, which hath been winnowed with
                the shovel and with the fan.      --Is. xxx. 24.
          [1913 Webster]

   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.
      [1913 Webster]

   3. A quintain; -- from its form. [Obs.] --Chaucer.
      [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fan
    n 1: a device for creating a current of air by movement of a
         surface or surfaces
    2: an enthusiastic devotee of sports [syn: sports fan, fan,
       rooter]
    3: an ardent follower and admirer [syn: fan, buff,
       devotee, lover]
    v 1: strike out (a batter), (of a pitcher)
    2: make (an emotion) fiercer; "fan hatred"
    3: agitate the air
    4: separate the chaff from by using air currents; "She stood
       there winnowing chaff all day in the field" [syn: winnow,
       fan]

Moby Thesaurus II by Grady Ward, 1.0:

303 Moby Thesaurus words for "fan":
   Maecenas, V, abettor, adherent, admirer, advocate, aerate, aerator,
   aficionado, agitate, air, air conditioner, air cooler, air filter,
   air out, air passage, air-condition, air-cool, airify, airscrew,
   amateur, angel, annoy, apologist, appendage, applauder,
   appreciator, arouse, attendant, attender, audience, authority,
   awake, awaken, backer, blow the coals, blow up, blower, bomb,
   booster, branch, branch out, buff, bug, call forth, call up,
   cavaliere servente, champion, chiller, claqueur, cold pack,
   collector, commender, connoisseur, cooler, cooling system,
   courtier, crank, crap out, critic, cross-ventilate, crotch, crutch,
   dangler, defender, delta, dependence, dependent, deploy, devotee,
   dilettante, disciple, disperse, draw a blank, driver, drop a bomb,
   drop the ball, electric fan, encomiast, encourager, endorser,
   energumen, enkindle, enrage, enthusiast, eulogist, eulogizer,
   excite, exhaust fan, expand, expert, exponent, extend, extoller,
   fan out, fan the fire, fan the flame, fanatic, fanatico, fancier,
   favorer, feed the fire, ferment, fire, flabellum, flame, flare,
   flop, flummox, flunky, fold, fold up, follower, following, foment,
   fork, freak, frenzy, frequenter, freshen, friend at court, frisk,
   furcula, furculum, get left, groin, groupie, habitue, hanger-on,
   haunter, heat, heat up, henchman, homme de cour, hound, ice bag,
   ice bucket, ice cube, ice pack, ice pail, idolater, idolizer,
   impassion, impeller, incense, incite, infatuate, inflame,
   infuriate, inguen, instigate, key up, kindle, lather up, lauder,
   lay an egg, light the fuse, light up, lose out, lover,
   lunatic fringe, madden, mainstay, maintainer, monomaniac, move,
   nettle, not hack it, not make it, nut, offshoot, open, open up,
   outspread, outstretch, overexcite, overgrow, overrun, oxygenate,
   oxygenize, paddle wheel, panegyrist, paranymph, parasite, partisan,
   patron, pique, piston, plugger, praiser, promoter, prong, prop,
   propellant, propeller, propulsor, protagonist, provoke, public,
   puffer, pundit, punkah, pursuer, pursuivant, put up to, rally,
   ramification, ramify, refresh, reliance, rooter, rotor, rouse,
   ruffle, satellite, savant, scholar, screw, screw propeller, second,
   seconder, sectary, set astir, set fire to, set on, set on fire,
   shadow, shake down, sic on, sider, specialist, spectator, splay,
   sponsor, spraddle, sprangle, sprawl, spread, spread like wildfire,
   spread out, stalwart, standby, steam up, stem, stir,
   stir the blood, stir the embers, stir the feelings, stir up,
   stooge, strike out, successor, summon up, support, supporter,
   surface cooler, sustainer, sympathizer, tagtail, tail,
   take the count, technical expert, technician, theatergoer,
   thermantidote, tickle, tout, touter, trainbearer, trident, turbine,
   turn on, twin screws, unfold, upholder, ventilate, ventilator,
   visitor, votary, wake, wake up, waken, ward heeler, warm,
   warm the blood, water cooler, well-wisher, wheel, whet, whiff,
   whip up, widen, wind, windcatcher, windsail, windscoop,
   wine cooler, winnow, wishbone, work into, work up, worshiper,
   zealot



The Jargon File (version 4.4.7, 29 Dec 2003):

fan
 n.

    Without qualification, indicates a fan of science fiction, especially one
    who goes to cons and tends to hang out with other fans. Many hackers are
    fans, so this term has been imported from fannish slang; however, unlike
    much fannish slang it is recognized by most non-fannish hackers. Among SF
    fans the plural is correctly fen, but this usage is not automatic to
    hackers. ?Laura reads the stuff occasionally but isn't really a fan.?


Easton's 1897 Bible Dictionary:

Fan
   a winnowing shovel by which grain was thrown up against the wind
   that it might be cleansed from broken straw and chaff (Isa.
   30:24; Jer. 15:7; Matt. 3:12). (See AGRICULTURE.)