- 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
Examples from the Web for chorion
Historical Examples of 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.
In the Cheiroptera (Vespertilio and Pteropus), the yolk-sack is large, and coalesces with part of the chorion.
The allantoic cavity persists (Owen), but the allantois only covers the placental area 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
Word Origin 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).
- The outer membrane enclosing the embryo in reptiles, birds, and mammals. In placental mammals it contributes to the development of the placenta.
- The outer membrane that encloses the embryo of a reptile, bird, or mammal. In mammals, the chorion contributes to the development of the placenta.