- A transparent inner eyelid in wild birds, reptiles, many mammals that closes to guard and dampen a person's eye. Also called third eyelid.
- a transparent safety fold of skin acting as an inner eyelid in wild birds, reptiles and some mammals
- a protective fold of skin when you look at the eyes of reptiles and wild birds many mammals
- a thin membrane, present in many pets at the internal direction, or beneath the reduced top, of attention, and with the capacity of becoming drawn across the eyeball; the next eyelid; the haw.
Hyponym for "nictitating membrane"
Hypernym for "nictitating membrane"