Oleic acid is a type of fatty acid found in many foods and oils. It is an unsaturated omega-9 fatty acid, meaning it has one double bond in its structure. Oleic acid is the most common fatty acid found in nature, and is found in high concentrations in olive oil, avocado oil, and other plant-based oils. It is also found in animal fats, such as lard and tallow. Oleic acid is used in the production of soaps, detergents, and cosmetics, and is also used as a food additive.