lactone lac·tone (lāk'tōn')
An anhydride formed by the removal of a water molecule from the hydroxyl and carboxyl radicals of hydroxy acids.
Any of various organic esters derived from organic acids by removal of water. Lactones are formed when the carboxyl (COOH) group of the acid reacts with a hydroxyl (OH) group in the same acid, releasing water and causing the carbon atom to join to the hydroxyl's remaining oxygen atom, forming a ring. Vitamin C, the antibiotic erythromycin, and many commercially important substances are lactones.