chorioallantois; chorioallantoic membrane
Anatomical term for the fused chorion and allantois in embryonic development; used in biology and medicine.
The chorioallantois is involved in gas exchange in the embryos of birds and reptiles.
Compound of 漿 (しょう, 'serous fluid') + 尿 (にょう, 'urine') + 膜 (まく, 'membrane'), reflecting the fusion of the serous chorion and the allantois.