[kawr-ee-oh-uh-lan-toh-is, ‐tois, kohr‐]
noun Embryology, Zoology.
a vascular, extraembryonic membrane of birds, reptiles, and certain mammals, formed by the fusion of the wall of the chorion with the wall of the allantois.
- chorioadenoma destruens,
- choriocapillary layer
Origin of chorioallantois
First recorded in 1930–35
Also called chorioallantoic membrane.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
The highly vascular extraembryonic membrane formed by the fusion of the allantois with the chorion that constitutes the placenta in most mammals.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.