noun, plural pla·cen·tas, pla·cen·tae [pluh-sen-tee] /pləˈsɛn ti/.
- the part of the ovary of flowering plants that bears the ovules.
- (in ferns and related plants) the tissue giving rise to sporangia.
Origin of placenta
Examples from the Web for placental
Historical Examples of placental
Sometimes the thrombus may be traced back to the placental site.
The allantoic cavity persists (Owen), but the allantois only covers the placental area of the chorion.The Works of Francis Maitland Balfour, Volume III (of 4)
Francis Maitland Balfour
Each of two females, captured on January 13, carried five placental scars; one of the females was lactating.The Recent Mammals of Tamaulipas, Mexico
The animals distinguished by this quality are grouped together as the Placental Mammals.The Art of Logical Thinking
William Walker Atkinson
From marsupial animals, marsupials will issue; from placental ones, those that are placental.History of the Intellectual Development of Europe, Volume II (of 2)
John William Draper
noun plural -tas or -tae (-tiː)
- the part of the ovary of flowering plants to which the ovules are attached
- the mass of tissue in nonflowering plants that bears the sporangia or spores
Word Origin for placenta
1808, from Modern Latin placentalis, from placenta (see placenta).
1670s of plants, 1690s of mammals, from Modern Latin placenta uterina "uterine cake" (so called 16c. by Italian anatomist Realdo Colombo), from Latin placenta "a cake, flat cake," from Greek plakoenta, accusative of plakoeis "flat," related to plax (genitive plakos) "level surface, anything flat," from PIE *plak- (1) "to be flat" (cf. Greek plakoeis "flat," Lettish plakt "to become flat," Old Norse flaga "layer of earth," Norwegian flag "open sea," Old English floh "piece of stone, fragment," Old High German fluoh "cliff"), extended form of root *pele- (2) "flat, to spread" (see plane (n.1)). So called from the shape.
n. pl. pla•cen•tas
An organ that forms in the uterus after the implantation of a zygote. The placenta moves nourishment from the mother's blood to the embryo or fetus; it also sends the embryo or fetus's waste products into the mother's blood to be disposed of by the mother's excretory system. The embryo or fetus is attached to the placenta by the umbilical cord. After birth, the placenta separates from the uterus and is pushed out of the mother's body.