malonic acidPronunciation: /məˈlɒnɪk/Definition of malonic acid noun [mass noun] Chemistry a crystalline acid obtained by the oxidation of malic acid. Chemical formula: HOOCCH2COOH Origin: mid 19th century: malonic from French malonique, alteration of malique 'malic'malonic acid in other Oxford dictionaries Definition of malonic acid in the US English dictionary