- 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
- the innermost of two membranes enclosing an embryonic reptile, bird, or mammalSee also chorion
Word Origin and History for amnia
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