Empirin n 1: the acetylated derivative of salicylic acid; used as an analgesic anti-inflammatory drug (trade names Bayer, Empirin, and St. Joseph) usually taken in tablet form; used as an antipyretic; slows clotting of the blood by poisoning platelets [syn: {aspirin}, {acetylsalicylic acid}, {Bayer}, {Empirin}, {St. Joseph}]