Cyclic esters, also known as lactones, are a type of organic compound formed when a carboxylic acid reacts with an alcohol, resulting in a ring structure. They are characterized by a closed loop of carbon atoms, which includes an ester functional group. Cyclic esters can vary in size, typically containing three to thirteen carbon atoms in the ring. These compounds are commonly found in nature and are responsible for various flavors and fragrances. Some cyclic esters, like γ-butyrolactone, are used in industrial applications, while others, such as caprolactone, are important in the production of biodegradable polymers.