1. The outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)

Derived forms: chorions

See also: chorionic

Type of: sac

Part of: amniote, fetal membrane

Encyclopedia: Chorion

• circumflex humeral artery
• circumflex iliac artery
• circumflex iliac vein
• circumflex scapular artery
• circumflex vein
• circumfluous
• circumfuse
• circumjacent
• circumlocution
• circumlocutious
• circumlocutory
• circumnavigate
• circumnavigation
• circumnavigator
• circumpolar
• circumscribe
• circumscribed
• circumscription
• circumspect
• circumspection
• circumspectly
• circumstance
• circumstances
• circumstantial
• circumstantial evidence