allantois

noun al·lan·to·is \ ə-ˈlan-tə-wəs \

Definition of allantois

plural allantoides play \ˌa-lən-ˈtō-ə-ˌdēz, ˌa-ˌlan-\

: 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

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allantoic

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

Origin and Etymology of allantois

New Latin, ultimately from Greek allant-, allas sausage

NEW! Time Traveler

First Known Use: 1615

in the meaning defined above

See Words from the same year

Medical Dictionary

allantois

noun al·lan·to·is \ ə-ˈlant-ə-wəs \

medical Definition of allantois

plural allantoides play \ˌal-ən-ˈtō-ə-ˌdēz, ˌal-ˌan-\

: 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