noun pl. placentas or placentae
- Anat., Zool.
- a vascular organ, developed within the uterus of most mammals during gestation from the chorion of the embryo and a part of the maternal uterine wall, that is connected to the embryo by the umbilical cord and that is discharged shortly after birth: it serves as the structure through which nourishment for the fetus is received from, and wastes of the fetus are eliminated into, the circulatory system of the mother
- any similar structure in other animals
- that part of the lining of the ovary which bears the ovules
- any mass of tissue that bears sporangia or spores
ModL < L, lit., a cake < Gr plakounta, acc. of plakous, a flat cake < plax (gen. plakos), a flat object < IE base *plāk-, flat > L placere, to please