amnion
Americannoun
plural
amnions, amnia-
Anatomy, Zoology. the innermost of the embryonic or fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended.
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Zoology. a similar membrane of insects and other invertebrates.
noun
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A thin, membranous sac filled with a watery fluid (called the amniotic fluid) in which the embryo or fetus of a reptile, bird, or mammal is suspended during prenatal development.
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Also called amniotic sac
Etymology
Origin of amnion
1660–70; < Greek, equivalent to amn ( ós ) lamb ( see yean) + -ion diminutive suffix
Vocabulary lists containing amnion
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.
He had two emergency corneal transplants and three amnion grafts, where tissue from the inner lining of a donated placenta was used to save his eye.
From BBC • Feb. 19, 2025
But a single placenta can make anywhere between 50 to 100 amnion grafts.
From BBC • Feb. 19, 2025
A method to correctly specify amnion formation is important to be able to recapitulate human embryo development as closely as possible using stem cell-based embryo models.
From Science Daily • Mar. 4, 2024
Based on this phylogeny, a student asks “Does this mean that lizards, frogs and rabbits all possessed hair and an egg with amnion at some point in their evolution?”
From Textbooks • Jun. 9, 2022
The innermost envelope, the amnion, encloses the foetus.
From Common Diseases of Farm Animals by Craig, R. A., D. V. M.
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
