AMNION Meaning of AMNION in English n. (pl. amnia) Zool. & Physiol. the innermost membrane that encloses the embryo of a reptile, bird, or mammal. amniotic adj.[ Gk, = caul (dimin. of amnos lamb) ] Concise Oxford English dictionary. Краткий оксфордский словарь английского языка. 2012