placenta
noun
pla·cen·ta
plə-ˈsen-tə 
plural placentas or placentae
plə-ˈsen-(ˌ)tē
1
: the vascular organ in mammals except monotremes and marsupials that unites the fetus to the maternal uterus and mediates its metabolic exchanges through a more or less intimate association of uterine mucosal with chorionic and usually allantoic tissues
also
: an analogous organ in another animal
2
: a sporangium-bearing surface
especially
: the part of the carpel bearing ovules
Examples of placenta in a Sentence
Recent Examples on the Web
Pregnant people should also take extra precautions around wildfire smoke, which can cross the placenta and affect a developing fetus.
—
Karen Kaplan, Los Angeles Times, 8 Jan. 2025
The screening – which is routinely offered to all pregnant people – involves analyzing cell-free DNA fragments from the placenta that circulate in the mother’s bloodstream.
—Jacqueline Howard, CNN, 16 Dec. 2024
The ultrasound revealed that her placenta was covering her cervix—a condition, known as placenta previa, that heightened her risk of hemorrhage or preterm birth.
—Stephania Taladrid, The New Yorker, 25 Nov. 2024
Share [Findings] Microplastics were found in sixty-two of sixty-two human placentas from a biobank in Texas.
—Rafil Kroll-Zaidi, Harper's Magazine, 2 Jan. 2025
See all Example Sentences for placenta 
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
Karen Kaplan, Los Angeles Times, 8 Jan. 2025
The screening – which is routinely offered to all pregnant people – involves analyzing cell-free DNA fragments from the placenta that circulate in the mother’s bloodstream.
—Jacqueline Howard, CNN, 16 Dec. 2024
The ultrasound revealed that her placenta was covering her cervix—a condition, known as placenta previa, that heightened her risk of hemorrhage or preterm birth.
—Stephania Taladrid, The New Yorker, 25 Nov. 2024
Share [Findings] Microplastics were found in sixty-two of sixty-two human placentas from a biobank in Texas.
—Rafil Kroll-Zaidi, Harper's Magazine, 2 Jan. 2025
See all Example Sentences for placenta
Dictionary Entries Near placenta
Cite this Entry
“Placenta.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/placenta. Accessed 24 Jan. 2025.
Copy CitationKids Definition
placenta
noun
pla·cen·ta
plə-ˈsent-ə
plural placentas or placentae
-ˈsent-ē
: the organ in most mammals by which the fetus is joined to the uterus of the mother and is nourished
placental
adjective
-ˈsent-ᵊl
Medical Definition
placenta
noun
pla·cen·ta
plə-ˈsent-ə
plural placentas or placentae
-ˈsent-(ˌ)ē
: the vascular organ in mammals except monotremes and marsupials that unites the fetus to the maternal uterus and mediates its metabolic exchanges through a more or less intimate association of uterine mucosal with chorionic and usually allantoic tissues permitting exchange of material by diffusion between the maternal and fetal vascular systems but without direct contact between maternal and fetal blood and typically involving the interlocking of fingerlike vascular chorionic villi with corresponding modified areas of the uterine mucosa see abruptio placentae
Love words? Need even more definitions?
Merriam-Webster unabridged
Share