placenta

[ pluh-sen-tuh ]
/ pləˈsɛn tə /

noun, plural pla·cen·tas, pla·cen·tae [pluh-sen-tee] /pləˈsɛn ti/.

Anatomy, Zoology. 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.
Botany.
  1. the part of the ovary of flowering plants that bears the ovules.
  2. (in ferns and related plants) the tissue giving rise to sporangia.

Origin of placenta

1670–80; < New Latin: something having a flat, circular form, Latin: a cake < Greek plakóenta, accusative of plakóeis flat cake, derivative of pláx (genitive plakós) flat
Related forms
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for placenta

British Dictionary definitions for placenta

placenta

/ (pləˈsɛntə) /

noun plural -tas or -tae (-tiː)

the vascular organ formed in the uterus during pregnancy, consisting of both maternal and embryonic tissues and providing oxygen and nutrients for the fetus and transfer of waste products from the fetal to the maternal blood circulationSee also afterbirth
the corresponding organ or part in certain mammals
botany
  1. the part of the ovary of flowering plants to which the ovules are attached
  2. the mass of tissue in nonflowering plants that bears the sporangia or spores

Word Origin for placenta

C17: via Latin from Greek plakoeis flat cake, from plax flat
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for placenta

placenta

[ plə-sĕntə ]

n. pl. pla•cen•tas

The membranous vascular organ in female mammals that permits metabolic interchange between fetus and mother. It develops during pregnancy from the chorion of the embryo and the decidua basalis of the maternal uterus and permits the absorption of oxygen and nutritive materials into the fetal blood and the release of carbon dioxide and nitrogenous waste from it, without the direct mixing of maternal and fetal blood. It is expelled following birth.

Related formspla•cental adj.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for placenta

placenta

[ plə-sĕntə ]

The sac-shaped organ that attaches the embryo or fetus to the uterus during pregnancy in most mammals. Blood flows between mother and fetus through the placenta, supplying oxygen and nutrients to the fetus and carrying away fetal waste products. The placenta is expelled after birth.
The part of the ovary of a flowering plant to which the ovules are attached. In a green pepper, for example, the whitish tissue to which the seeds are attached is the placenta.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Culture definitions for placenta

placenta

[ (pluh-sen-tuh) ]

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.


The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.