Zona /(?)/

Zo·na

Zona

n.

pl. Zonae

  1. A zone or band; a layer.

Phrases & Compounds
Zona pellucida
The outer transparent layer, or envelope, of the ovum. It is a more or less elastic membrane with radiating striae, and corresponds to the cell wall of an ordinary cell. See Ovum, and Illust. of Microscope.
Zona radiata
a radiately striated membrane situated next the yolk of an ovum, or separated from it by a very delicate membrane only.