1
a
: a piece of transparent material (such as glass) that has two opposite regular surfaces either both curved or one curved and the other plane and that is used either singly or combined in an optical instrument for forming an image by focusing rays of light
b
: a combination of two or more simple lenses
c
: a piece of glass or plastic used (as in safety goggles or sunglasses) to protect the eye
2
: a device for directing or focusing radiation other than light (such as sound waves, radio microwaves, or electrons)
3
: something shaped like a biconvex optical lens
lens of sandstone
4
: a highly transparent biconvex lens-shaped or nearly spherical body in the eye that focuses light rays (as upon the retina) see eye illustration
5
: something that facilitates and influences perception, comprehension, or evaluation
viewing the current legal battle … through partisan lenses—
New Republic
New RepublicExamples of lens in a Sentence
Noun
Make sure the lens of the microscope is clean.
Recent Examples on the WebEugene Linden, TIME, 21 Apr. 2024
Nearly six feet tall with long blond hair and usually toting a camera lens the size of a small howitzer, Groo is soft-spoken and deliberate.
—Rene Ebersole, Rolling Stone, 21 Apr. 2024
See all Example Sentences for lens 
Noun
First published in 1989 by W.W. Norton, author John Perlin looked at the rise and fall of civilizations through the lens of the forests that supported them, and then showed how, time after time, subsequent deforestation contributed to a civilization’s collapse.
—Eugene Linden, TIME, 21 Apr. 2024
Nearly six feet tall with long blond hair and usually toting a camera lens the size of a small howitzer, Groo is soft-spoken and deliberate.
—Rene Ebersole, Rolling Stone, 21 Apr. 2024
See all Example Sentences for lens
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'lens.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near lens
Cite this Entry
“Lens.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lens. Accessed 4 May. 2024.
Copy CitationMedical Definition
lens
noun
variants
also lense
1
: a curved piece of glass or plastic used singly or combined in eyeglasses or an optical instrument (as a microscope) for forming an image by focusing rays of light
2
: a device for directing or focusing radiation other than light (as sound waves, radio microwaves, or electrons)
3
: a highly transparent biconvex lens-shaped or nearly spherical body in the eye that focuses light rays entering the eye typically onto the retina, lies immediately behind the pupil, is made up of slender curved rod-shaped ectodermal cells in concentric lamellae surrounded by a tenuous mesoblastic capsule, and alters its focal length by becoming more or less spherical in response to the action of the ciliary muscle on a peripheral suspensory ligament
lensed
adjective
lensless
adjective
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