油酸 (yóu suān), or oleic acid, is a monounsaturated fatty acid commonly found in various animal and vegetable fats. It is a key component of many oils, such as 橄榄油 (olive oil) and 葵花籽油 (sunflower oil), and is known for its health benefits, including promoting heart health and reducing inflammation. In addition to its dietary importance, 油酸 is used in the production of soaps, cosmetics, and lubricants. Its chemical structure allows it to act as an emulsifier, helping to blend oil and water in various products, making it valuable in both food and industrial applications.