- a white, bitter, crystalline alkaloid, C17H19NO3⋅H2O, the most important narcotic and addictive principle of opium, obtained by extraction and crystallization and used chiefly in medicine as a pain reliever and sedative.
- an alkaloid extracted from opium: used in medicine as an analgesic and sedative, although repeated use causes addiction. Formula: C 17 H 19 NO 3
