amnios Meaning, Definition & Usage

1. noun thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
   amnion; amniotic sac.
   
2. noun (pregnancy) extraction by centesis of amniotic fluid from a pregnant woman (after the 15th week of pregnancy) to aid in the diagnosis of fetal abnormalities
   amniocentesis; amnio.
   

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