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meconium

American  
[mi-koh-nee-uhm] / mɪˈkoʊ ni əm /

noun

  1. the first fecal excretion of a newborn child, composed chiefly of bile, mucus, and epithelial cells.

  2. fecal mass released at pupation by the larvae of some insects.

  3. the milky sap of the unripe seed pods of the opium poppy; crude opium.


meconium British  
/ mɪˈkəʊnɪəm /

noun

  1. the dark green mucoid material that forms the first faeces of a newborn infant

  2. opium or the juice from the opium poppy

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of meconium

1595–1605; < Latin < Greek mēkṓnion, diminutive of mḗkōn poppy

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

They’ve also been detected in blood, breast milk and even meconium — an infant’s first stool.

From Los Angeles Times • Apr. 2, 2026

The following day, traces of meconium – a baby's first poo – were detected, which can be a sign of distress in a baby.

From BBC • Dec. 9, 2024

The group is now investigating the occurrence of microbial metabolites in other mammals: piglets and calves, as well as in the meconium and amniotic fluid samples of babies.

From Science Daily • Nov. 1, 2023

Lo wrote that doctors discovered her newborn swallowed meconium, which led to pneumonia.

From Los Angeles Times • Oct. 11, 2023

A rectal injection of one tablespoonful of warm water is given at once to unload the bowels of the meconium; this generally acts before the baby's toilet is completed.

From The Four Epochs of Woman's Life; a study in hygiene by Galbraith, Anna M. (Anna Mary)