Medicine & BodyGreek → English
Chorion
/ˈkɔriɑn/noun
The outermost membrane enclosing the embryo, which develops into part of the placenta.
The Greek roots
χόριον
chórion
fetal membrane, afterbirth
Literally: “membrane, skin”
Follow a root:χόριον1 word
The story of the word
Greek medical writers used χόριον both for the membrane around a fetus and for the afterbirth itself, and the same word could mean a skin or a sheet of leather. English medicine borrowed it in the seventeenth century and kept the sense narrow. The prenatal test called chorionic villus sampling takes a few cells from precisely the tissue the Greek word named, some weeks earlier than amniocentesis can be done.
- How it travelled
- Ancient Greek → New Latin → English
- First recorded
- 17th century
Same family
chorionicchoriocarcinomachorioamnionitis
In a sentence
By week twelve the chorion has fused with the uterine wall.
Insect eggs have a chorion too, though it is a shell rather than a membrane.