Lexic.us

Definition of Third eyelid

1. Noun. A protective fold of skin in the eyes of reptiles and birds and some mammals.

Medical Definition of Third eyelid

1. The semilunar fold formed by the palpebral conjunctiva at the medial angle of the eye, a fold of the conjunctival mucous membrane found in many animals; normally partially hidden in the medial canthus of the eye when at rest, it may be extended to cover part or all of the cornea in a winking-like action to clean the cornea, as in birds. Synonym: membrana nictitans, nictitating membrane, palpebra III, palpebra tertia, third eyelid. Synonym: plica lunata, plica semilunaris of eye, semilunar conjunctival fold. (05 Mar 2000)

Lexicographical Neighbors of Third Eyelid

Literary usage of Third eyelid

Below you will find example usage of this term as found in modern and/or classical literature:

1. On the Anatomy of Vertebrates by Richard Owen (1868)
"... have many excretory orifices upon the margin of the third eyelid, but its principal duct terminates upon the inner surface near the base of that lid. ..."

2. The Dog and the Sportsman: Embracing the Uses, Breeding, Training, Diseases by John Stuart Skinner (1845)
"It is sometimes called, on account of its function, the third eyelid. The dog is more adroit in the use of his paws than many other animals are, ..."

3. The Dog and the Sportsman: Embracing the Uses, Breeding, Training, Diseases by John Stuart Skinner (1845)
"ENLARGEMENT OF THE third eyelid. The quadruped not having hands to ward off some dangers which threaten him, and to which the eyes are particularly exposed, ..."

4. Horse and Man: Their Mutual Dependence and Duties by John George Wood (1885)
"... third eyelid, or ' nictitating membrane ' and its use—The groom's rashness and its effects. WE have not quite finished with the horse's head. ..."

5. Paley's Natural Theology by William Paley, Henry Brougham Brougham and Vaux, Charles Bell, Elisha Bartlett (1839)
"This third eyelid is a very peculiar part of the apparatus of protection. It is a thin cartilage, the posterior part of which, is attached to an elastic ..."

6. The Encyclopaedia Britannica: A Dictionary of Arts, Sciences, and General by Thomas Spencer Baynes (1888)
"There is often a third eyelid, which can be drawn obliquely over the eye, ... There is a rudiment of a third eyelid, and there is a bony plate in the lower ..."

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