Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun allantois

1 sense of allantois

Sense 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))
       => fetal membrane -- (any membrane that functions for the protection or nourishment or respiration or excretion of a developing fetus)