Malic acid is a common organic acid found in fruits such as apples, pears, and grapes. It is also used as a food additive and in the production of certain pharmaceuticals. There are several synonyms for malic acid, including hydroxy butanedioic acid, 2-hydroxybutanedioic acid, and alpha-hydroxybutyric acid. These terms refer to the same compound, which has a sour taste and is a key component in the metabolism of many organisms. Malic acid is also used in the production of some wines, where it can influence the taste and acidity of the final product. Overall, malic acid is an important compound for understanding the chemistry of many foods and biological processes.