Source : Webster's Revised Unabridged Dictionary (1913)

Meconin \Mec"o*nin\, n. [Cf. F. m['e]conine.] (Chem.)
   A substance regarded as an anhydride of meconinic acid,
   existing in opium and extracted as a white crystalline
   substance. Also erroneously called meconina, meconia, etc.,
   as though it were an alkaloid.