Definition of amnion
1 : a thin membrane forming a closed sac about the embryos or fetuses of reptiles, birds, and mammals and containing the amniotic fluid
2 : a membrane analogous to the amnion and occurring in various invertebrates
amnioticplay \ˌam-nē-ˈä-tik\ adjective
Seen and Heard
What made you want to look up amnion? Please tell us where you read or heard it (including the quote, if possible).