The Collaborative International Dictionary of English v.0.48:

Blast \Blast\ (bl[.a]st), n. [AS. bl[=ae]st a puff of wind, a
   blowing; akin to Icel. bl[=a]str, OHG. bl[=a]st, and fr. a
   verb akin to Icel. bl[=a]sa to blow, OHG. bl[^a]san, Goth.
   bl[=e]san (in comp.); all prob. from the same root as E.
   blow. See Blow to eject air.]
   1. A violent gust of wind.
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            And see where surly Winter passes off,
            Far to the north, and calls his ruffian blasts;
            His blasts obey, and quit the howling hill.
                                                  --Thomson.
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   2. A forcible stream of air from an orifice, as from a
      bellows, the mouth, etc. Hence: The continuous blowing to
      which one charge of ore or metal is subjected in a
      furnace; as, to melt so many tons of iron at a blast.
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   Note: The terms hot blast and cold blast are employed to
         designate whether the current is heated or not heated
         before entering the furnace. A blast furnace is said to
         be in blast while it is in operation, and out of blast
         when not in use.
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   3. The exhaust steam from and engine, driving a column of air
      out of a boiler chimney, and thus creating an intense
      draught through the fire; also, any draught produced by
      the blast.
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   4. The sound made by blowing a wind instrument; strictly, the
      sound produces at one breath.
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            One blast upon his bugle horn
            Were worth a thousand men.            --Sir W.
                                                  Scott.
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            The blast of triumph o'er thy grave.  --Bryant.
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   5. A sudden, pernicious effect, as if by a noxious wind,
      especially on animals and plants; a blight.
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            By the blast of God they perish.      --Job iv. 9.
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            Virtue preserved from fell destruction's blast.
                                                  --Shak.
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   6. The act of rending, or attempting to rend, heavy masses of
      rock, earth, etc., by the explosion of gunpowder,
      dynamite, etc.; also, the charge used for this purpose.
      "Large blasts are often used." --Tomlinson.
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   7. A flatulent disease of sheep.
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   Blast furnace, a furnace, usually a shaft furnace for
      smelting ores, into which air is forced by pressure.

   Blast hole, a hole in the bottom of a pump stock through
      which water enters.

   Blast nozzle, a fixed or variable orifice in the delivery
      end of a blast pipe; -- called also blast orifice.

   In full blast, in complete operation; in a state of great
      activity. See Blast, n., 2. [Colloq.]
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WordNet (r) 3.0 (2006):

blast furnace
    n 1: a furnace for smelting of iron from iron oxide ores;
         combustion is intensified by a blast of air