heroin

her·o·in

noun \ˈher-ə-wən\

Definition of HEROIN

: a strongly physiologically addictive narcotic C₂₁H₂₃NO₅ that is made by acetylation of but is more potent than morphine and that is prohibited for medical use in the United States but is used illicitly for its euphoric effects—called also acetomorphine, diacetylmorphine, diamorphine