- Embryology. the outermost of the extraembryonic membranes of land vertebrates, contributing to the formation of the placenta in the placental mammals.
- Zoology. the membrane around the eggs of certain insects, secreted by cells of the ovary.
Origin of chorion
1535–45; < New Latin < Greek chórion membrane enclosing the fetus
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for chorion
The chorion is often ornamented with various processes, etc.The Works of Francis Maitland Balfour, Volume II (of 4)
Francis Maitland Balfour
The chorion is an outward skin which compasseth the child in the womb.
The allantoic cavity persists (Owen), but the allantois only covers the placental area of the chorion.
In the Cheiroptera (Vespertilio and Pteropus), the yolk-sack is large, and coalesces with part of the chorion.
This form of placenta occupies a broad zone of the chorion, leaving the two poles free.
- the outer of two membranes that form a sac around the embryonic reptile, bird, or mammal: contributes to the placenta in mammalsSee also amnion
C16: from Greek khorion afterbirth
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for chorion
"outer membrane of the fetus," 1540s, medical Latin, from Greek khorion "membrane enclosing the fetus, afterbirth," perhaps from PIE *ghere- "gut, entrail" (see yarn).
Online Etymology Dictionary, © 2010 Douglas Harper
- The outer membrane enclosing the embryo in reptiles, birds, and mammals. In placental mammals it contributes to the development of the placenta.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
- The outer membrane that encloses the embryo of a reptile, bird, or mammal. In mammals, the chorion contributes to the development of the placenta.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.