— placental, placentary /plas"euhn ter'ee, pleuh sen"teuh ree/ , adj.
/pleuh sen"teuh/ , n. , pl. placentas, placentae /-tee/ .
1. Anat. , Zool. the organ in most mammals, formed in the lining of the uterus by the union of the uterine mucous membrane with the membranes of the fetus, that provides for the nourishment of the fetus and the elimination of its waste products.
2. Bot.
a. the part of the ovary of flowering plants that bears the ovules.
b. (in ferns and related plants) the tissue giving rise to sporangia.
[ 1670-80; plakóenta, acc. of plakóeis flat cake, deriv. of pláx (gen. plakós ) flat ]