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

The researchers combined the six chemicals into a placenta-relevant PFAS mixture and exposed it to a 3D trophoblast model—an advanced system that mimics the spherical cell architecture of early placental tissue far more accurately than traditional flat cultures. —Daniella Gray, MSNBC Newsweek, 5 Dec. 2025

Doctors diagnosed me with complete placenta previa. —Kobi V. Ajayi, The Conversation, 1 Dec. 2025

Another video shows that Cardi also opted for a placenta print, which is another service the company offers. —Hannah Sacks, PEOPLE, 24 Nov. 2025

It can also be transmitted through aborted fetuses, placental fluids or placentas from infected horses. —Steven Yablonski, CBS News, 21 Nov. 2025

Word History

Etymology

New Latin, from Latin, flat cake, from Greek plakoenta, accusative of plakoeis, from plak-, plax flat surface — more at fluke entry 2

First Known Use

1638, in the meaning defined at sense 1

Rhymes for placenta

• magenta
• momenta
• placentae
• impedimenta
• presidente

Kids 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

-ˈsent-ᵊl

adjective

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