Source : Webster's Revised Unabridged Dictionary (1913)

Wart \Wart\, n. [OE. werte, AS. wearte; akin to D. wrat, G.
   warze, OHG. warza, Icel. varta, Sw. v[*a]rta, Dan. vorte;
   perh. orig., a growth, and akin to E. wort; or cf. L. verruca
   wart.]
   1. (Med.) A small, usually hard, tumor on the skin formed by
      enlargement of its vascular papill[ae], and thickening of
      the epidermis which covers them.

   2. An excrescence or protuberance more or less resembling a
      true wart; specifically (Bot.), a glandular excrescence or
      hardened protuberance on plants.

   {Fig wart}, {Moist wart} (Med.), a soft, bright red, pointed
      or tufted tumor found about the genitals, often massed
      into groups of large size. It is a variety of condyloma.
      Called also {pointed wart}, {venereal wart}. --L. A.
      Duhring.

   {Wart cress} (Bot.), the swine's cress. See under {Swine}.

   {Wart snake} (Zo["o]l.), any one of several species of East
      Indian colubrine snakes of the genus {Acrochordus}, having
      the body covered with wartlike tubercles or spinose
      scales, and lacking cephalic plates and ventral scutes.

   {Wart spurge} (Bot.), a kind of wartwort ({Euphorbia
      Helioscopia}).

Source : WordNet®

wart
     n 1: any small rounded protuberance (as on certain plants or
          animals)
     2: (pathology) a firm abnormal elevated blemish on the skin;
        caused by a virus [syn: {verruca}]

Source : Free On-Line Dictionary of Computing

wart
     
        A small, {crock}y {feature} that sticks out of an otherwise
        {clean} design.  Something conspicuous for localised ugliness,
        especially a special-case exception to a general rule.  For
        example, in some versions of "csh(1)", single quotes
        literalise every character inside them except "!".  In ANSI C,
        the "?" syntax used for obtaining ASCII characters in a
        foreign environment is a wart.  See also {miswart}.
     
        [{Jargon File}]