eyelid

[ahy-lid]
noun
the movable lid of skin that serves to cover and uncover the eyeball.

Origin:
1200–50; Middle English; see eye, lid

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
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Collins
World English Dictionary
eyelid (ˈaɪˌlɪd)
 
n
1.  either of the two muscular folds of skin that can be moved to cover the exposed portion of the eyeballRelated: palpebral
2.  aeronautics Also called: clamshell a set of movable parts at the rear of a jet engine that redirect the exhaust flow to assist braking during landing
 
Related: palpebral

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline
Word Origin & History

eyelid
mid-13c., from eye + lid.
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

eyelid eye·lid or eye-lid (ī'lĭd')
n.
Either of two folds of skin and muscle that can be closed over the exposed portion of the eyeball. Also called palpebra.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Britannica
Encyclopedia

eyelid

movable tissue, consisting primarily of skin and muscle, that shields and protects the eyeball from mechanical injury and helps to provide the moist chamber essential for the normal functioning of the conjunctiva and cornea. The conjunctiva is the mucous membrane that lines the eyelid and covers the visible portion of the eyeball except the cornea (the transparent part of the eyeball that covers the iris and the pupil). Each eyelid contains a fibrous plate, called a tarsus, that gives it structure and shape; muscles, which move the eyelids; and meibomian (or tarsal) glands, which secrete lubricating fluids. The lids are covered with skin, lined with mucous membrane, and bordered with a fringe of hairs, the eyelashes. The lids move through the action of a circular lid-closing muscle, the orbicularis oculi, and of the lid-raising muscle, the levator of the upper lid. Impulses for closing come by way of the facial (seventh cranial) nerve, and for opening by way of the oculomotor (third cranial) nerve. The lid borders are kept lubricated by an oily secretion (called sebum) of the meibomian glands. This secretion forms part of the tear film and reduces evaporative tear loss.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
Sometimes his eyelid is too weak to make the selections.
One side of her face eyelid and mouth, was pulled sharply down.
The shuttered eyelid gracing the cover of this slim book invites readers to
  enter a silent realm.
Finally it pierces the orbital septum, and ends in the skin of the upper
  eyelid, joining with filaments of the facial nerve.
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