amnion

[ am-nee-uhn ]

noun

, plural am·ni·ons, am·ni·a [am, -nee-, uh].

1. Anatomy, Zoology. the innermost of the embryonic or fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended.
2. Zoology. a similar membrane of insects and other invertebrates.

amnion

/ ˈæmnɪən /

noun

1. the innermost of two membranes enclosing an embryonic reptile, bird, or mammal See also chorion

amnion

/ ăm′nē-ən /

1. 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.
2. Also called amniotic sac

Word History and Origins

Origin of amnion¹

1660–70; < Greek, equivalent to amn ( ós ) lamb ( yean ) + -ion diminutive suffix

Word History and Origins

Origin of amnion¹

C17: via New Latin from Greek: a little lamb, from amnos a lamb

Example Sentences

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

Its major adaptive advantage is the amnion — an enclosing membrane that prevents the embryo from drying out, and the principal feature to which the amniotic egg owes its name.

From Nature

Until recently, pre-natal screening required invasive procedures such as amniocentesis, in which the fluid from the sac surrounding the foetus, the amnion, is sampled and the DNA examined for genetic abnormalities.

From Scientific American

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 Project Gutenberg

Of or pertaining to the amnion; characterized by an amnion; as, the amniotic fluid; the amniotic sac. ÷ acid.

From Project Gutenberg