Esters are organic compounds formed from the reaction between an alcohol and a carboxylic acid. They are characterized by a functional group that includes a carbon atom double-bonded to an oxygen atom and single-bonded to another oxygen atom, which is in turn bonded to a carbon chain. Esters often have pleasant, fruity odors and are commonly found in nature, contributing to the scents of many fruits and flowers. In addition to their natural occurrence, esters are widely used in the food and fragrance industries as flavoring agents and scent compounds. They are also important in the production of polymers, such as polyester, which is used in textiles and plastics.