1. that part of the ovary of a flowering plant where the ovules form • Derivationally related forms: placental • Hypernyms: reproductive structure • Part Holonyms: ovary 2. the vascular structure in the uterus of most mammals providing oxygen and nutrients for and transferring wastes from the developing fetus • Derivationally related forms: placental • Hypernyms: vascular structure • Hyponyms: afterbirth • Part Holonyms: uterus, womb • Part Meronyms: caul, veil, embryonic membrane