the conversion of an ester heated with an alkali into the corresponding alcohol and acid salt; specif., this process carried out with fats (glyceryl esters) to produce soap
See saponification in American Heritage Dictionary 4
(sə-pŏnˌə-fĭ-kāˈshən)
noun
A reaction in which an ester is heated with an alkali, such as sodium hydroxide, producing a free alcohol and an acid salt, especially alkaline hydrolysis of a fat or oil to make soap.