Medical Dictionary

nictitating membrane


Medical Definition of NICTITATING MEMBRANE

:  a thin membrane found in many vertebrate animals at the inner angle or beneath the lower lid of the eye and capable of extending across the eyeball—called also membrana nictitans, third eyelid


How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears