5,8,11,14-Eicosatetraenoic (icosatetraenoic) acid; an unsaturated fatty acid, usually essential in nutrition; the biological precursor of the prostaglandins, the thromboxanes, and the leukotrienes (collectively known as eicosanoids).
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ar·a·chi·don·ic acid .ar-ə-kə-.dän-ik- n a liquid unsaturated fatty acid C20H32O2 that occurs in most animal fats, is a precursor of prostaglandins, and is considered essential in animal nutrition
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arach·i·don·ic ac·id (ə-rak″ĭ-donґik) a polyunsaturated 20-carbon essential fatty acid (see table at fatty acid) occurring in animal fats and also formed by biosynthesis from dietary linoleic acid. It is a precursor in the biosynthesis of leukotrienes, prostaglandins, and thromboxanes.Medical dictionary. 2011.