The Collaborative International Dictionary
Subzonal
Subzonal \Sub*zon"al\, a. (Anat.) Situated under a zone, or zona; -- applied to a membrane between the zona radiata and the umbilical vesicle in the mammal embryo.
Wiktionary
subzonal
a. 1 Relating to a subzone. 2 (context anatomy English) Situated under a zone, or zona; applied to a membrane between the zona radiata and the umbilical vesicle in the mammal embryo.