Definition of Allantois in English :

Define Allantois in English

Allantois meaning in English

Meaning of Allantois in English

Pronunciation of Allantois in English

Allantois pronunciation in English

Pronounce Allantois in English


see synonyms of allantois


1. allantois

the vascular fetal membrane that lies below the chorion and develops from the hindgut in many embryonic higher vertebrates (reptiles, birds and mammals)

WordNet Lexical Database for English. Princeton University. 2010.


see synonyms of allantois
a membranous sac growing out of the ventral surface of the hind gut of embryonic reptiles, birds, and mammals. It combines with the chorion to form the mammalian placenta

Collins English Dictionary. Copyright © HarperCollins Publishers


see synonyms of allantois
nounWord forms: plural ˌallanˈtoiˌdes (ˌælənˈtoʊəˌdiz ; alˌəntōˈədēzˌ)
a membranous pouch with a rich blood supply in the embryos of birds, reptiles, and mammals: it is an organ of respiration and excretion for embryonic birds and reptiles: in mammals it helps form the placenta

Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by Houghton Mifflin Harcourt. All rights reserved.


see synonyms of allantois
n. pl. al·lan·to·i·des (ălən-tōĭ-dēz)
A membranous sac that develops from the posterior part of the digestive tract in the embryos of mammals, birds, and reptiles. It is important in the formation of the umbilical cord and placenta in mammals. Also called allantoid.

The American Heritage ® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.