| Webster's Online Dictionary |
| Expressions | Domain | Definition | |
| Fetal Membranes | Health | Thin layers of tissue which surround the embryo or fetus and provide for its nutrition, respiration, excretion and protection; they are the yolk sac, allantois, amnion, and chorion. (references) | |
Source: compiled by the editor from various references; see credits. | Top | ||
