- the dark green mucoid material that forms the first faeces of a newborn infant
WordReference Random House Unabridged Dictionary of American English © 2026
me•co•ni•um
(mi kō′nē əm),USA pronunciation n.
- Physiologythe first fecal excretion of a newborn child, composed chiefly of bile, mucus, and epithelial cells.
- Insectsfecal mass released at pupation by the larvae of some insects.
- Drugs, Botanythe milky sap of the unripe seed pods of the opium poppy;
crude opium.
- Greek mēkó̄nion, diminutive of mé̄kōn poppy
- Latin
- 1595–1605
Collins Concise English Dictionary © HarperCollins Publishers::
meconium /mɪˈkəʊnɪəm/ n