A substance thought to be an anhydride of meconinic acid, within opium.
A substance thought to be an anhydride of meconinic acid, current in opium and removed as a white crystalline substance. In addition erroneously called meconina, meconia, etc., as if it had been an alkaloid.
A neutral material (C10H10O4) current in opium. It's white, fusible, and crystalline.
How would you define meconin?