The Collaborative International Dictionary of English v.0.48:

Cool \Cool\, v. t. [imp. & p. p. Cooled; p. pr. & vb. n.
   Cooling.]
   1. To make cool or cold; to reduce the temperature of; as,
      ice cools water.
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            Send Lazarus, that he may dip the tip of his finger
            in water, and cool my tongue.         --Luke xvi.
                                                  24.
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   2. To moderate the heat or excitement of; to allay, as
      passion of any kind; to calm; to moderate.
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            We have reason to cool our raging motions, our
            carnal stings, our unbitted lusts.    --Shak.
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   To cool the heels, to dance attendance; to wait, as for
      admission to a patron's house. [Colloq.] --Dryden.
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The Collaborative International Dictionary of English v.0.48:

Cooling \Cool"ing\, p. a.
   Adapted to cool and refresh; allaying heat. "The cooling
   brook." --Goldsmith.
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   Cooling card, something that dashes hopes. [Obs.]

   Cooling time (Law), such a lapse of time as ought, taking
      all the circumstances of the case in view, to produce a
      subsiding of passion previously provoked. --Wharton.
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WordNet (r) 3.0 (2006):

cooling
    n 1: the process of becoming cooler; a falling temperature [syn:
         cooling, chilling, temperature reduction]
    2: a mechanism for keeping something cool; "the cooling was
       overhead fans" [syn: cooling system, cooling]