Noun
thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
Source: WordNetDuring amniocentesis, fluid is removed by placing a long needle through the abdominal wall into amniotic sac. Source: Internet
The clear fluid in the amniotic sac that surrounds the fetus during pregnancy. Source: Internet
Your baby is growing in a bag of protective fluid called the amniotic sac. Source: Internet