Organic acids are a group of chemicals that contain one or more carboxyl groups (-COOH). These acids are generally derived from living organisms, and are classified as weak acids due to their ability to donate a hydrogen ion (H+) when in solution. Some common examples include acetic acid, citric acid, and lactic acid. There are also several synonyms for organic acid, including carboxylic acid, fatty acid, and aliphatic acid. Carboxylic acid is a more precise term since it includes all organic acids containing a carboxyl group, while fatty acids are a subgroup of carboxylic acids that are typically long-chain and found in fats. Aliphatic acids are simply organic acids that do not contain any aromatic rings.