Arachidic acid, also called eicosanoic acid, is the saturated fatty acid with a 20 carbon chain. It is as a minor constituent of peanut oil (1.1%–1.7%) and corn oil (3%). Its name derives from the Latin arachis — peanut. It can be formed by the hydrogenation of arachidonic acid.
Reduction of arachidic acid yields arachidyl alcohol.
Arachidic acid is used for the production of detergents, photographic materials and lubricants.