acetylsalicylic acid

(organic chemistry) CH₃COOC₆H₄COOH A white, crystalline, weakly acidic substance, with melting point 137°C; slightly soluble in water; used medicinally as an antipyretic. Also known by trade name aspirin.

A white crystalline powder which is a non-steroidal anti-inflammatory drug (NSAID), used as an antipyretic to treat headaches and as a mild analgesic to relieve pain. It is also widely used to treat muscle and joint injuries, arthritis, and cardiovascular disorders. It tends to increase clotting time and, therefore, increases the tendency of a person to bleed. Consequently, it can be harmful to individuals with stomach or duodenal ulcers. A few individuals are allergic to aspirin; if they ingest it they could go into an anaphylactic shock. Aspirin is a permissible drug, not on the World Anti-Doping Agency's 2005 Prohibited List.

The noun has one meaning:

Meaning #1: the acetylated derivative of salicylic acid; used as an analgesic anti-inflammatory drug (trade names Bayer and Empirin) usually taken in tablet form; used as an antipyretic; slows clotting of the blood by poisoning platelets
  Synonyms: aspirin, Bayer, Empirin