- A structure formed on the wall of the uterus during pregnancy which serves to exchange oxygen, wastes and nutrients between the mother's blood and the embryo/fetus' blood; the placenta is expelled as afterbirth.
There are several types of placentas:
- In plants: a region, within an ovary, to which ovules are attached.
From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.