nictitating membrane

nic·ti·tat·ing membrane

 (nĭk′tĭ-tā′tĭng)

n.

A transparent inner eyelid in many vertebrates that closes to protect and moisten the eye. Also called third eyelid.

nictitating membrane

(ˈnɪktɪˌteɪtɪŋ)

n

(Zoology) (in reptiles, birds, and some mammals) a thin fold of skin beneath the eyelid that can be drawn across the eye. Also called: third eyelid or haw

nic′titating mem′brane

n.

a thin membrane, present in many animals, that can be drawn across the eyeball for protection.

[1705–15]

nic·ti·tat·ing membrane

(nĭk′tĭ-tā′tĭng)

A transparent inner eyelid in birds, reptiles, amphibians, and some mammals that protects and moistens the eye without blocking vision.

Thesaurus

Noun

1.

nictitating membrane - a protective fold of skin in the eyes of reptiles and birds and some mammals third eyelid eye, oculus, optic - the organ of sight protective fold - a flap of tissue that protects what it covers haw - the nictitating membrane of a horse