placenta
Americannoun
plural
placentas, placentae-
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.
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Botany.
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the part of the ovary of flowering plants that bears the ovules.
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(in ferns and related plants) the tissue giving rise to sporangia.
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noun
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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 circulation See also afterbirth
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the corresponding organ or part in certain mammals
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botany
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the part of the ovary of flowering plants to which the ovules are attached
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the mass of tissue in nonflowering plants that bears the sporangia or spores
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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.
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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.
Other Word Forms
- interplacental adjective
- nonplacental adjective
- placental adjective
- placentary adjective
- preplacental adjective
- subplacenta noun
- subplacental adjective
Etymology
Origin of placenta
First recorded in 1670–80; from New Latin: “something having a flat, circular form,” Latin: “cake,” from Greek plakóenta, accusative of plakóeis “flat cake,” derivative of pláx (stem plak- ) “flat”
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Deposits of black carbon from air pollution have been found in the human body including in placentas analysed after birth.
From BBC
It's a rare and potentially life-threatening condition when twins share one placenta.
From BBC
Evolution repurposed ancient infections into essential parts of human biology, including the placenta and adaptive immunity.
Late in her third trimester, doctors diagnosed her with placenta accreta, a potentially life-threatening condition in which the placenta grows too far into the wall of the uterus.
They have already been detected in breast milk and in the placenta -- and even in the brain.
From Science Daily
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.