allantois

noun
al·lan·to·is | \ə-ˈlan-tə-wəs \
plural allantoides\ˌa-lən-ˈtō-ə-ˌdēz, ˌa-ˌlan- \

Definition of allantois 

: a vascular fetal membrane of reptiles, birds, and mammals that is formed as a pouch from the hindgut and that in placental mammals is intimately associated with the chorion in formation of the placenta

Other Words from allantois

allantoic \ˌa-lən-ˈtō-ik, ˌa-ˌlan- \ adjective

First Known Use of allantois

1615, in the meaning defined above

History and Etymology for allantois

New Latin, ultimately from Greek allant-, allas sausage

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The first known use of allantois was in 1615

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allantois

noun
al·lan·to·is | \ə-ˈlant-ə-wəs \
plural allantoides\ˌal-ən-ˈtō-ə-ˌdēz, ˌal-ˌan- \

Medical Definition of allantois 

: a vascular fetal membrane of reptiles, birds, or mammals that is formed as a pouch from the hindgut and that in placental mammals is intimately associated with the chorion in formation of the placenta

More from Merriam-Webster on allantois

Britannica.com: Encyclopedia article about allantois

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