1. Thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
   "The amnios provides a protective fluid environment for the developing foetus";
   - amnion, amniotic sac

1. (pregnancy) extraction by centesis of amniotic fluid from a pregnant woman (after the 15th week of pregnancy) to aid in the diagnosis of foetal abnormalities
   "She opted for amnio to check for genetic disorders";
   - amniocentesis

Type of: centesis, prenatal diagnosis, sac

Part of: amniote, fetal membrane

Encyclopedia: Amnios