The Collaborative International Dictionary of English v.0.48:

Burn \Burn\ (b[^u]rn), v. t. [imp. & p. p. Burned (b[^u]rnd)
   or Burnt (b[^u]rnt); p. pr. & vb. n. Burning.] [OE.
   bernen, brennen, v. t., early confused with beornen, birnen,
   v. i., AS. b[ae]rnan, bernan, v. t., birnan, v. i.; akin to
   OS. brinnan, OFries. barna, berna, OHG. brinnan, brennan, G.
   brennen, OD. bernen, D. branden, Dan. br[ae]nde, Sw.
   br[aum]nna, brinna, Icel. brenna, Goth. brinnan, brannjan (in
   comp.), and possibly to E. fervent.]
   1. To consume with fire; to reduce to ashes by the action of
      heat or fire; -- frequently intensified by up: as, to burn
      up wood. "We'll burn his body in the holy place." --Shak.
      [1913 Webster]

   2. To injure by fire or heat; to change destructively some
      property or properties of, by undue exposure to fire or
      heat; to scorch; to scald; to blister; to singe; to char;
      to sear; as, to burn steel in forging; to burn one's face
      in the sun; the sun burns the grass.
      [1913 Webster]

   3. To perfect or improve by fire or heat; to submit to the
      action of fire or heat for some economic purpose; to
      destroy or change some property or properties of, by
      exposure to fire or heat in due degree for obtaining a
      desired residuum, product, or effect; to bake; as, to burn
      clay in making bricks or pottery; to burn wood so as to
      produce charcoal; to burn limestone for the lime.
      [1913 Webster]

   4. To make or produce, as an effect or result, by the
      application of fire or heat; as, to burn a hole; to burn
      charcoal; to burn letters into a block.
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   5. To consume, injure, or change the condition of, as if by
      action of fire or heat; to affect as fire or heat does;
      as, to burn the mouth with pepper.
      [1913 Webster]

            This tyrant fever burns me up.        --Shak.
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            This dry sorrow burns up all my tears. --Dryden.
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            When the cold north wind bloweth, . . . it devoureth
            the mountains, and burneth the wilderness, and
            consumeth the ??ass as fire.          --Ecclus.
                                                  xliii. 20, 21.
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   6. (Surg.) To apply a cautery to; to cauterize.
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   7. (Chem.) To cause to combine with oxygen or other active
      agent, with evolution of heat; to consume; to oxidize; as,
      a man burns a certain amount of carbon at each
      respiration; to burn iron in oxygen.
      [1913 Webster]

   To burn, To burn together, as two surfaces of metal
      (Engin.), to fuse and unite them by pouring over them a
      quantity of the same metal in a liquid state.

   To burn a bowl (Game of Bowls), to displace it
      accidentally, the bowl so displaced being said to be
      burned.

   To burn daylight, to light candles before it is dark; to
      waste time; to perform superfluous actions. --Shak.

   To burn one's fingers, to get one's self into unexpected
      trouble, as by interfering the concerns of others,
      speculation, etc.

   To burn out,
      (a) to destroy or obliterate by burning. "Must you with
          hot irons burn out mine eyes?" --Shak.
      (b) to force (people) to flee by burning their homes or
          places of business; as, the rioters burned out the
          Chinese businessmen.

   To be burned out, to suffer loss by fire, as the burning of
      one's house, store, or shop, with the contents.

   To burn up, To burn down, to burn entirely.
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The Collaborative International Dictionary of English v.0.48:

Burnt \Burnt\, p. p. & a.
   Consumed with, or as with, fire; scorched or dried, as with
   fire or heat; baked or hardened in the fire or the sun.
   [1913 Webster]

   Burnt ear, a black, powdery fungus which destroys grain.
      See Smut.

   Burnt offering, something offered and burnt on an altar, as
      an atonement for sin; a sacrifice. The offerings of the
      Jews were a clean animal, as an ox, a calf, a goat, or a
      sheep; or some vegetable substance, as bread, or ears of
      wheat or barley. Called also burnt sacrifice. --[2 Sam.
      xxiv. 22.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

burnt
    adj 1: ruined by overcooking; "she served us underdone bacon and
           burnt biscuits" [syn: burned, burnt]
    2: treated by heating to a high temperature but below the
       melting or fusing point; "burnt sienna" [syn: burned,
       burnt]
    3: destroyed or badly damaged by fire; "a row of burned houses";
       "a charred bit of burnt wood"; "a burned-over site in the
       forest"; "barricaded the street with burnt-out cars" [syn:
       burned, burnt, burned-over, burned-out, burnt-out]