third eyelid

• Membrane transparente ou semi-transparente présente dans l'œil de nombreux animaux comme les oiseaux, les reptiles et certains mammifères, qui se déplace horizontalement sur l'œil pour le protéger et l'humidifier ; chez l'humain, c'est une structure rudimentaire connue sous le nom de pli semi-lunaire.

A transparent or translucent nictitating membrane found in the eyes of many animals, such as birds, reptiles, and some mammals, which moves horizontally across the eye to protect and moisten it; in humans, it is a vestigial structure known as the plica semilunaris.

1. Nictitating membraneC1formal

   A transparent or translucent third eyelid present in some animals, such as birds, reptiles, and some mammals, that moves horizontally across the eye for protection and moisture.

   troisième paupière

   • Cats have a third eyelid that helps protect their eyes from dust.
   • The veterinarian checked the dog's third eyelid for signs of infection.
   • Birds use their third eyelid to keep their eyes clean while flying.