chorion

noun

cho·​ri·​on ˈkȯr-ē-ˌän 

plural chorions or choria ˈkȯr-ē-ə 

1

: the highly vascular outer membrane of the amniotic sac that in placental mammals is associated with the allantois in the formation of the placenta

2

: the outer shell of an insect's egg

Examples of chorion in a Sentence

Recent Examples on the Web

If the split is delayed, usually a week or so after conception, the processes of growing a placenta, chorion, and amniotic sac are already underway. — Pamela Prindle Fierro, Parents, 30 July 2024

This is essentially a blood clot that can occur when the outermost membrane surrounding the embryo (the chorion) separates a little from the uterine wall, allowing some blood to pool in that space between the two. — Amy Marturana, SELF, 28 Dec. 2018

Word History

Etymology

New Latin, from Greek, afterbirth

First Known Use

1545, in the meaning defined at sense 1

Rhymes for chorion

• corean
• dorian
• saurian
• gregorian
• historian
• nestorian
• praetorian
• stentorian
• pythagorean
• valedictorian

Kids Definition

chorion

noun

cho·​ri·​on ˈkōr-ē-ˌän 

ˈkȯr-

: the outer membrane that surrounds the embryo of reptiles, birds, and mammals and that in mammals with a placenta contributes to the formation of the placenta

chorionic

ˌkōr-ē-ˈän-ik, 

ˌkȯr-

adjective

Medical Definition

chorion

noun

cho·​ri·​on ˈkōr-ē-ˌän, ˈkȯr- 

: the highly vascular outer embryonic membrane that is associated with the allantois in the formation of the placenta