a crystalline acid, COOHCHCH(OH)COOH, occurring in apples and other fruits
See malic acid in American Heritage Dictionary 4
(mălˈĭk, māˈlĭk)
noun
A colorless, crystalline compound, COOH·CH2·CHOH·COOH, that occurs naturally in a wide variety of unripe fruit, including apples, cherries, and tomatoes, and is used as a flavoring and in the aging of wine.