- Anatomy, Zoology. the innermost of the embryonic or fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended.
- Zoology. a similar membrane of insects and other invertebrates.
Origin of amnion
Examples from the Web for amnion
Amnion: the inner of the two membranes enveloping the embryo.Explanation of Terms Used in Entomology
John. B. Smith
The embryo when about to hatch throws off the egg-shell and amnion in a few seconds.Our Common Insects
Alpheus Spring Packard
Only in the chancel were they protected by sheep's amnion stretched on frames.Pabo, The Priest
The amnion contains a fluid known by the name of liquor amnii.A System of Midwifery
Both it and the stalk of the yolk-sack are enveloped by the amnion (am).The Works of Francis Maitland Balfour, Volume III (of 4)
Francis Maitland Balfour
- the innermost of two membranes enclosing an embryonic reptile, bird, or mammalSee also chorion
Word Origin and History for amnion
1660s, Modern Latin, from Greek amnion "membrane around a fetus," said to be originally "bowl in which the blood of victims was caught" [Liddell & Scott], which is variously said to be of unknown origin, from ame "bucket," or a diminutive of amnos "lamb."
- The thin, membranous sac filled with a serous fluid in which the embryo or fetus is enclosed and suspended in the uterus.amniotic sac
- 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. Also called amniotic sac