achaian
- n a member of one of four linguistic divisions of the prehistoric Greeks
acetylcholine
- n a neurotransmitter that is a derivative of choline; released at the ends of nerve fibers in the somatic and parasympathetic nervous systems
acetylene
- n a colorless flammable gas used chiefly in welding and in organic synthesis
acetylsalicylic acid
- n 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
achaea
- n a region of ancient Greece on the north coast of the Peloponnese