phenobarbital

phe·no·bar·bi·tal

noun \ˌfē-nō-ˈbär-bə-ˌtȯl, -tȧl\

Definition of PHENOBARBITAL

: a crystalline barbiturate C₁₂H₁₂N₂O₃ that is used orally or is administered by injection in the form of its sodium salt C₁₂H₁₁N₂NaO₃ as a hypnotic and sedative—see luminal