Crack \Crack\ (kr[a^]k), v. t. [imp. & p. p. {Cracked}
   (kr[a^]kt); p. pr. & vb. n. {Cracking}.] [OE. cracken,
   craken, to crack, break, boast, AS. cracian, cearcian, to
   crack; akin to D. kraken, G. krachen; cf. Skr. garj to
   rattle, or perh. of imitative origin. Cf. {Crake},
   {Cracknel}, {Creak}.]
   
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   1. To break or burst, with or without entire separation of
      the parts; as, to crack glass; to crack nuts.
      
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   2. To rend with grief or pain; to affect deeply with sorrow;
      hence, to disorder; to distract; to craze.
      
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            O, madam, my old heart is cracked.    --Shak.
      
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            He thought none poets till their brains were
            cracked.                              --Roscommon.
      
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   3. To cause to sound suddenly and sharply; to snap; as, to
      crack a whip.
      
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   4. To utter smartly and sententiously; as, to crack a joke.
      --B. Jonson.
      
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   5. To cry up; to extol; -- followed by up. [Low]
      
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   {To crack a bottle}, to open the bottle and drink its
      contents.

   {To crack a crib}, to commit burglary. [Slang]

   {To crack on}, to put on; as, to crack on more sail, or more
      steam. [Colloq.]
      
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cracking \cracking\ n.
   1. the act of cracking something.

   Syn: fracture, crack.
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   2. (Chem.) the process of making lower molecular weight
      hydrocarbons from heavier hydrocarbons in petroleum, by
      exposure to heat and catalysts. It is used to convert
      heavier alkanes into gasoline, or to improve the octane
      number of an alkane mixture.
      [PJC]

cracking \cracking\ adj.
   same as {groovy}, sense 1. [informal]

   Syn: bang-up, bully, cool, corking, dandy, great, groovy,
        keen, neat, nifty, not bad(predicate), peachy, slap-up,
        swell, smashing.
        [WordNet 1.5]