Noun: amnion (amnia,amnions) am-nee-un
- Thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
"The amnion provides a protective fluid environment for the developing foetus";
- amniotic sac, amnios
Derived forms: amnions, amnia
Type of: sac
Part of: amniote, fetal membrane
Encyclopedia: Amnion