noun
the membrane that forms around a fertilized ovum and prevents penetration by additional spermatozoon
• Hypernyms: ↑membrane, ↑tissue layer
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noun : a resistant membranous layer that separates from the surface of many eggs immediately after entry of a sperm and thus prevents multiple fertilization
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fertilization membrane,
an extension of the membrane surrounding an egg, which prevents the entry of additional sperm after fertilization has occurred.
Useful english dictionary. 2012.