saponification
    n 1: a chemical reaction in which an ester is heated with an
         alkali (especially the alkaline hydrolysis of a fat or oil
         to make soap)

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.
   [1913 Webster]

Hydrolysis \Hy*drol"y*sis\, n. [Hydro-, 1 + -lysis.] (Chem.)
   A chemical process causing the splitting of a chemical bond
   by the addition of the elements of water. Where the bond
   which is split is not part of a ring structure, this process
   causes formation of two compounds from one compound plus
   water, as in the hydrolysis of the ester bonds of fats during
   saponification.
   [Webster 1913 Suppl. +PJC]