Source : Webster's Revised Unabridged Dictionary (1913)

Citric \Cit"ric\, a. [Cf. F. citrique. See {Citron}.] (Chem.)
   Of, pertaining to, or derived from, the citron or lemon; as,
   citric acid.

   {Citric acid} (Chem.), an organic acid, {C3H4OH.(CO2H)3},
      extracted from lemons, currants, gooseberries, etc., as a
      white crystalline substance, having a pleasant sour taste.

Source : WordNet®

citric acid
     n : a weak water-soluble acid found in many fruits (especially
         citrus fruits); used as a flavoring agent