1928 (morphine barbiturate is from 1918), from German, coined 1863 by chemist Adolf von Baeyer (1835-1917) from Barbitursäure "barbituric acid," itself coined by Baeyer, perhaps from woman's name Barbara, or perhaps from Latin barbata, in Medieval Latin usnea barbata, literally "bearded moss." Second element is because it was obtained from uric acid. With chemical ending -ate (3).
Any of a group of drugs that act as depressants of the central nervous system, are highly addictive, and are used primarily as sedatives and anticonvulsants. Phenobarbital and pentobarbital are examples of barbiturates.