the.com/amnion

means The thin, fluid-filled membrane that encloses and cushions an embryo or fetus inside the womb.

from Borrowed directly from Greek 'amnion,' a term the ancient Greeks used for the membrane around a fetus — itself thought to be related to 'amnos,' meaning lamb, possibly because the membrane was also noted in the birth sacs of sacrificial lambs. The word entered scientific Latin and then English largely unchanged, which is why it still sounds faintly ancient and ritualistic.