'Zona pellucida' definitions:
Definition of 'zona pellucida'
From: WordNet
noun
Thick membrane around the mammalian ovum; can be penetrated by one sperm in the fertilization process; usually remains around the fertilized egg until it is implanted in the wall of the uterus
Definition of 'Zona pellucida'
From: GCIDE
- Zona \Zo"na\, n.; pl. Zonae. [L., a girdle. See Zone.] A zone or band; a layer. [1913 Webster]
- Zona pellucida. [NL.] (Biol.) (a) 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. (b) The zona radiata.
- Zona radiata [NL.] (Biol.), a radiately striated membrane situated next the yolk of an ovum, or separated from it by a very delicate membrane only. [1913 Webster]