a fluid-filled membranous sac in the pregnant uterus that encloses and cushions the fetus, normally breaking at or just before the time of birth; the amnion.
Origin
1880-85
Examples from the web for bag of waters
The amnion and the chorion together are called the fetal membranes or the bag of waters.
Breaking of the bag of waters can be either a gush of water or a steady leak.
bag of waters in Medicine
bag of watersn. the amniotic sac and the amniotic fluid in it