amnion

Estimated CEFR level: C2 — Proficiency

Estimated from word frequency; not an official CEFR classification.

Definition

noun thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)

From Latin amnion (“membrane around a fetus”), from Ancient Greek ἀμνίον (amníon).

The embryo when about to hatch throws off the egg-shell and amnion in a few seconds. — Our Common Insects: A Popular Account of the Insects of Our Fields, Forests, Gardens and Houses, A. S. (Alpheus Spring) Packard
But we can say with comparative certainty that in our case ... in this case it is the amnion which is to blame." — Royal Highness, Thomas Mann

amniotic sac, amnios

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