Frost \Frost\ (fr[o^]st; 115), n. [OE. frost, forst, AS.
         forst,
   frost. fr. fre['o]san to freeze; akin to D.
         varst, G., OHG.,
   Icel., Dan., & Sw. frost. [root]18. See
         Freeze, v. i.]
   1. The
         act of freezing; -- applied chiefly to the congelation
    
          of water; congelation of fluids.
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          2. The state or temperature of the air which occasions
   
           congelation, or the freezing of water; severe cold or
   
           freezing weather.
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            The third bay comes a frost, a killing frost.
                                                  --Shak.
     
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   3. Frozen dew; -- called also
         hoarfrost or {white
         frost}.
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            He scattereth the hoarfrost like ashes. --Ps.
                                                  cxlvii. 16.
     
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   4. Coldness or insensibility; severity
         or rigidity of
      character. [R.]
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         Webster]

            It was of those moments of intense feeling when the
            frost of the Scottish people melts like a snow
            wreath.                               --Sir W.
                                                  Scott.
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         Webster]

   Black
         frost, cold so intense as to freeze
         vegetation and
      cause it to turn black, without the
         formation of
      hoarfrost.

   Frost bearer
         (Physics), a philosophical instrument
      illustrating
         the freezing of water in a vacuum; a
      cryophorus.

 
          Frost grape (Bot.),
         an American grape, with very small,

              acid berries.

   Frost lamp, a lamp placed below
         the oil tube of an Argand
      lamp to keep the oil limpid
         on cold nights; -- used
      especially in lighthouses.
         --Knight.

   Frost
         nail, a nail with a sharp head
         driven into a horse's
      shoe to keep him from
         slipping.

   Frost
         smoke, an appearance resembling
         smoke, caused by
      congelation of vapor in the
         atmosphere in time of severe
      cold.
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         Webster]

            The brig and the ice round her are covered by a
            strange black
            obscurity: it is the frost smoke of arctic winters.
                                                  --Kane.

  
         Frost valve, a valve
         to drain the portion of a pipe,
    
          hydrant, pump, etc., where water would be liable to
     
         freeze.

   Jack
         Frost, a popular personification of
         frost.
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