Mammals)

• Birds
• Outermost membranous sac enclosing the embryo in higher vertebrates (reptiles

Wikipedia Word definitions in Wikipedia
For the chorion in vertebrate eggs , see Chorion (egg) . For the entertainment company see Chorion (company) . In humans and most mammals, the chorion is one of the membranes that exist during pregnancy between the developing fetus and mother (the fetal ...

Wiktionary Word definitions in Wiktionary
n. 1 (context anatomy biology English) The protective and nutritive membrane in higher vertebrates that attaches the fetus to the uterus. 2 (context biology entomology English) The outer case of an insect egg. 3 (context botany English) The outer membrane ...

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Chorion \Cho"ri*on\, n. [NL., fr. Gr. ?.] (Anat.) The outer membrane which invests the fetus in the womb; also, the similar membrane investing many ova at certain stages of development. The true skin, or cutis. (Bot.) The outer membrane of seeds of plants. ...

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
"outer membrane of the fetus," 1540s, medical Latin, from Greek khorion "membrane enclosing the fetus, afterbirth," perhaps from PIE *ghere- "gut, entrail" (see yarn ).

WordNet Word definitions in WordNet
n. outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)