Lactones are a type of cyclic ester formed from the reaction of an alcohol and a carboxylic acid. They are characterized by a ring structure that includes an oxygen atom and are commonly found in nature. Lactones can have pleasant aromas and flavors, making them important in the food and fragrance industries. These compounds are classified based on the size of their ring, with common types including gamma-lactones and delta-lactones. Lactones are also significant in pharmaceuticals, where they can serve as building blocks for various drugs. Their unique properties make them valuable in both industrial and natural applications.