amnion
noun [ C ] biology specialized uk/ˈæm.ni.ən/ us/ˈæm.ni.ən/ amnions or amnia uk/ˈæm.ni.ə/ us/ˈæm.ni.ə/
（哺乳动物、鸟类或爬行动物胎儿的）羊膜
a bag made of thin skin that contains amniotic fluid and surrounds the embryo of a mammal, bird, or reptile inside its mother