Carboxylation refers to the process of adding a carboxyl (-COOH) functional group to a compound. There are several synonyms for this term, including carboxylating, carboxylic acid formation, and carboxylic acidification. Other related terms include decarboxylation (removal of a carboxyl group), carbonylation (addition of a carbonyl group), and esterification (formation of an ester from a carboxylic acid and an alcohol). Carboxylation plays an important role in various biological processes, such as the formation of citric acid in the Krebs cycle and the biosynthesis of fatty acids. It is also used in a range of industrial applications, including the production of food additives, pharmaceuticals, and polymers.