Definitions of Bayer:

noun: 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
name: A surname (rare: 1 in 33333 families; popularity rank in the U.S.: #3550)