01 n. A zone or band; a layer.
pl.
Zonae
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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.