WordNet
n. a protective fold of skin in the eyes of reptiles and birds and some mammals [syn: nictitating membrane]
Usage examples of "third eyelid".
His lashless eyelids made a rare blink, and his third eyelid -- the nictitating membrane -- was flickering more rapidly than usual.
The nictating membranes of the third eyelid retracted so that his eyes were fully open and bright as the highest caliber peridots.
Some animals have a third eyelid in the form of a transparent membrane that can be quickly drawn across the eye, usually in a horizontal sweep from the inner comer of the eye (the inner canthus) near the nose.
The lord of the mutants pinched his third eyelid shut and picked up his treasured M-60 machine gun.
His third eyelid, the nictitating membrane that covered his eye from the inner corner to the middle, had spread across his vision as it did when there was too much light or he was otherwise indisposed.
Light stabbed through his third eyelid, and he smelt the big dragon hovering above him.
He bases this on their skin color, and that third eyelid they have.
Piedmont opened one orange eye at the sound of her voice but he was not awake, his third eyelid remained half closed.
The third eyelid was already drawn half closed like a veil, signaling the nearness of death.