amnion
Americannoun
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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
Other Word Forms
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.
But a single placenta can make anywhere between 50 to 100 amnion grafts.
From BBC • Feb. 19, 2025
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
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
The amnion fills with amniotic fluid and eventually grows to surround the embryo.
From Textbooks • Jun. 19, 2013
The embryo of a moth, a dragon-fly or a bug is invaginated into the yolk at the head end, the portion of the blastoderm necessarily pushed in with it forming the amnion.
From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" by Various
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.
