acetaminophen n. 1.A white crystalline compound (HO.C6H4.NH.CO.CH3) used as an analgesic and also as an antipyretic. It has molecular weight 151.16. It is the active ingredient in the commercial analgesics Tylenol and Datril. Synonyms: p-hydroxyacetanilide, p-acetamidophenol, N-acetyl-p-aminophenol, paracetamol, N-(4-hydroxyphenyl)acetamide Note: It is sold under many trade names, and has been one of the most popular analgesics in the late 20th century. It is used in place of aspirin by people in whom aspirin causes undesirable side effects, such as stomach irritation or stomach bleeding.
