Found 2 items, similar to zona pellucida.
English → English (WordNet) Definition: zona pellucida zona pellucida n : 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
English → English (gcide) Definition: Zona pellucida Zona \Zo"na\, n.; pl. Zon[ae]. [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 stri[ae], 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]