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.

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.

• to convert a fat or oil into soap; to be converted into soap
  
• (chemistry) to hydrolyze an ester using an alkali