Definitions
from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A thin, tough, membranous sac that encloses the embryo or fetus of a mammal, bird, or reptile. It is filled with a serous fluid in which the embryo or fetus is suspended.
from The Century Dictionary.
- noun In echinoderms, the sac in the pluteus larva inclosing the developing echinus.
- noun In anatomy and vertebrate zoöl., one of the fetal appendages; the innermost one of the membranes which envelop the embryo of the higher vertebrates, as mammals, birds, and reptiles; the lining membrane of a shut sac, familiarly called the “bag of waters,” in which the fetus is contained.
- noun In entomology, a membrane which surrounds the larva of many insects, as the millepeds (Iulidæ), for some time after they are batched from the egg. It is regarded by some as the analogue of the amnion of a vertebrate.
- noun A reflected portion of a membrane, in ascidians, which lines the inner wall of the ovisac, and forms a kind of amniotic investment of the embryo.
- noun In botany, a name formerly given to the fluid contents of the embryo sac.
- noun Sometimes erroneously written amnios.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Anat.) A thin membrane surrounding the embryos of mammals, birds, and reptiles.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun anatomy the innermost
membrane of thefetal membranes of reptiles, birds, and mammals; thesac in which theembryo is suspended.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
Etymologies
from The American Heritage® Dictionary of the English Language, 4th Edition
from Wiktionary, Creative Commons Attribution/Share-Alike License
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Examples
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In these three classes alone we find the remarkable embryonic membrane, already mentioned, which we called the amnion; a cenogenetic adaptation that we may regard as a result of the sinking of the growing embryo into the yelk-sac.
The Evolution of Man — Volume 2 Ernst Heinrich Philipp August Haeckel 1876
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They described primitive cells found in a part of the placenta called the amnion, which they coaxed into forming a variety of cell types and which look very similar to sought-after embryonic stem cells.
Medpundit 2005
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They described primitive cells found in a part of the placenta called the amnion, which they coaxed into forming a variety of cell types and which look very similar to sought-after embryonic stem cells.
Archive 2005-08-01 2005
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The amnion is a membranous sac which surrounds and protects the embryo.
I. Embryology. 11. Development of the Fetal Membranes and Placenta 1918
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A great step in evolution was implied in the origin of this ante-natal hood or foetal membrane and another one -- of protective significance -- called the amnion, which forms a water-bag over the delicate embryo.
The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told J. Arthur Thomson 1897
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As the watery condition of the blood increases with advancing pregnancy, so dropsy of the amnion is a disease of the last four or five months of gestation.
Special Report on Diseases of the Horse Charles B. Michener 1877
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All the amniotes have a distinctive embryonic membrane known as the amnion
The Evolution of Man — Volume 1 Ernst Heinrich Philipp August Haeckel 1876
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After the egg has been fertilized by the male, the blastoderm, or primitive skin, forms, and subsequently two layers, or embryonal membranes, appear; the outer is called the amnion (Fig. 114, _am_), while the inner visceral membrane (_db_) partially wraps the rude form of the embryo in its folds.
Our Common Insects A Popular Account of the Insects of Our Fields, Forests, Gardens and Houses 1872
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They are caused by a tearing of the inner part of the placenta called the amnion, which produces the fiber-like bands that may trap the baby's extremities such as the arms, legs, fingers or toes.
Emaxhealth 2010
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They are caused by a tearing of the inner part of the placenta called the amnion, which produces the fiber-like bands that may trap the baby's extremities such as the arms, legs, fingers or toes.
Emaxhealth 2010
thelaughorist commented on the word amnion
I found this word in my reading today, from the memoir A Step from Death, by Larry Woiwode a great word in and of itself:
" . . . I feel my mind is treading water, so deep in moribund amnion I'll drown."
September 5, 2008