Arachidic acid, also known as eicosanoic acid, is a saturated fatty acid with a 20-carbon chain. It is as a minor constituent of cupuaçu butter (7%), peanut oil (1.1%–1.7%), corn oil (3%), and cocoa butter (1%).

Typical Fatty acid composition (%): Its name derives from the Latin arachis — peanut. It can be formed by the hydrogenation of arachidonic acid.