Source : Webster's Revised Unabridged Dictionary (1913)

Saponify \Sa*pon"i*fy\, v. t. [imp. & p. p. {Saponified}; p. pr.
   & vb. n. {Saponifying}.] [L. sapo, -onis, soap + -fy: cf. F.
   saponifier.]
   To convert into soap, as tallow or any fat; hence (Chem.), to
   subject to any similar process, as that which ethereal salts
   undergo in decomposition; as, to saponify ethyl acetate.