CHORIOALLANTOIS

[cho.rio.al.lan.to.is] n [NL, fr. Gk chorion + NL allantois] (1933): a vascular fetal membrane composed of the fused chorion and adjacent wall of the allantois that in the hen's egg is used as a living culture medium for viruses and for tissues--called also chorioallantoic membrane -- cho.rio.al.lan.to.ic adj