noun Anatomy.
the transparent anterior part of the external coat of the eye covering the iris and the pupil and continuous with the sclera.

1350–1400; Middle English < Medieval Latin cornea (tēla, later tunica) horny (web or tunic), feminine of corneus corneous

corneal, adjective
multicorneal, adjective
precorneal, adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
cornea (ˈkɔːnɪə)
n , pl -neas, -neae
the convex transparent membrane that forms the anterior covering of the eyeball and is continuous with the sclera
[C14: from Medieval Latin cornea tēla horny web, from Latin cornūhorn]

Collins English Dictionary - Complete & Unabridged 10th Edition
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Word Origin & History

late 14c., from M.L. cornea tela "horny web or sheath," from L. cornu (gen. cornus) "horn" (see horn). So called for its consistency.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

cornea cor·ne·a (kôr'nē-ə)
The transparent, convex, anterior portion of the outer fibrous coat of the eyeball that covers the iris and the pupil and is continuous with the sclera.

cor'ne·al adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
cornea   (kôr'nē-ə)  Pronunciation Key 
The tough transparent membrane of the outer layer of the eyeball that covers the iris and the pupil.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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American Heritage
Cultural Dictionary
cornea [(kawr-nee-uh)]

The transparent outer covering of the front of the eye that covers the iris and pupil.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Encyclopedia Britannica


dome-shaped transparent membrane about 12 mm (0.5 inch) in diameter that covers the front part of the eye. Except at its margins, the cornea contains no blood vessels, but it does contain many nerves and is very sensitive to pain or touch. It is nourished and provided with oxygen anteriorly by tears and is bathed posteriorly by aqueous humour. It protects the pupil, the iris, and the inside of the eye from penetration by foreign bodies and is the first and most powerful element in the eye's focusing system. As light passes through the cornea, it is partially refracted before reaching the lens. The curvature of the cornea, which is spherical in infancy but changes with age, gives it its focusing power; when the curve becomes irregular, it causes a focusing defect called astigmatism, in which images appear elongated or distorted.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
Cocaine is rarely used today as an anesthetic, both because of its addictive
  potential and because it degrades the cornea.
Patients with impaired vision because of a damaged cornea could soon regain
  their sight without need of a human donor transplant.
They can even grow blood vessels in the cornea of the eye, where otherwise none
  will grow.
Adult stem cells and cornea stem cells are two other possible sources for
  generating immature photoreceptor cells.
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