Source : Webster's Revised Unabridged Dictionary (1913)

Saponification \Sa*pon`i*fi*ca"tion\, n. [Cf. F. saponification.
   See {Saponify}.]
   The act, process, or result, of soap making; conversion into
   soap; specifically (Chem.), the decomposition of fats and
   other ethereal salts by alkalies; as, the saponification of
   ethyl acetate.

Source : WordNet®

saponification
     n : a chemical reaction in which an ester is heated with an
         alkali (especially the alkaline hydrolysis of a fat or
         oil to make soap)