The Collaborative International Dictionary of English v.0.48:

Concoct \Con*coct"\, v. t. [imp. & p. p. Concocted; p. pr. &
   vb. n. Concocting.] [L. concoctus, p. p. of concoquere to
   cook together, to digest, mature; con- + coquere to cook. See
   Cook.]
   1. To digest; to convert into nourishment by the organs of
      nutrition. [Obs.]
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            Food is concocted, the heart beats, the blood
            circulates.                           --Cheyne.
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   2. To purify or refine chemically. [Obs.] --Thomson.
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   3. To prepare from crude materials, as food; to invent or
      prepare by combining different ingredients; as, to concoct
      a new dish or beverage.
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   4. To digest in the mind; to devise; to make up; to contrive;
      to plan; to plot.
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            He was a man of a feeble stomach, unable to concoct
            any great fortune.                    --Hayward.
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   5. To mature or perfect; to ripen. [Obs.] --Bacon.
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WordNet (r) 3.0 (2006):

concoct
    v 1: make a concoction (of) by mixing
    2: prepare or cook by mixing ingredients; "concoct a strange
       mixture" [syn: concoct, cook up]
    3: invent; "trump up charges" [syn: trump up, concoct]
    4: devise or invent; "He thought up a plan to get rich quickly";
       "no-one had ever thought of such a clever piece of software"
       [syn: think up, think of, dream up, hatch, concoct]