ChEBI: Octadecanoic acid is a C18 straight-chain saturated fatty acid component of many animal and vegetable lipids. As well as in the diet, it is used in hardening soaps, softening plastics and in making cosmetics, candles and plastics. It has a role as a plant metabolite, a human metabolite, a Daphnia magna metabolite and an algal metabolite. It is a long-chain fatty acid, a straight-chain saturated fatty acid and a saturated fatty acid. It is a conjugate acid of an octadecanoate. It derives from a hydride of an octadecane.NCI Thesaurus (NCIt): Stearic Acid is a saturated long-chain fatty acid with an 18-carbon backbone. Stearic acid is found in various animal and plant fats, and is a major component of cocoa butter and shea butter.