lens

/lɛnz/

/lɛnz/

A lens is a curved transparent device that bends light, like the lens of eyeglasses or a contact lens you’ll need if the natural lens in your eye needs help. Cameras have a lens, too. Smile!

In an eye, the lens — which is behind the iris — helps focus light on the retina so you can see. It's a lot like the lens in a telescope or camera, which also focuses light and helps form images. You can also use the word lens as a metaphor for how you see things. If you look at sports through the lens of medicine, you might study injuries to players. All these lenses help you see or perceive things.

Definitions of lens

1. noun

   a transparent optical device used to converge or diverge transmitted light and to form images
   synonyms: lens system, lense

   types:

   anastigmat

   compound lens or lens system designed to be free of astigmatism and able to form approximately point images

   anastigmatic lens

   a lens designed to correct astigmatism

   camera lens, optical lens

   a lens that focuses the image in a camera

   compound lens

   a lens system consisting of two or more lenses on the same axis

   condenser, optical condenser

   lens used to concentrate light on an object

   contact, contact lens

   a thin curved glass or plastic lens designed to fit over the cornea in order to correct vision or to deliver medication

   converging lens, convex lens

   lens such that a beam of light passing through it is brought to a point or focus

   crown lens

   a lens made of optical crown glass

   concave lens, diverging lens

   a lens such that a parallel beam of light passing through it is caused to diverge or spread out

   eyepiece, ocular

   combination of lenses at the viewing end of optical instruments

   field lens

   the lens that is farthest from the eye in an optical device with more than one lens

   Fresnel lens

   lens composed of a number of small lenses arranged to make a lightweight lens of large diameter and short focal length

   intraocular lens

   an artificial lens that is implanted into the eye of someone to replace a damaged natural lens or someone who has had a cataract removed

   meniscus

   (optics) a lens that is concave on one side and convex on the other

   eyeglass, monocle

   lens for correcting defective vision in one eye; held in place by facial muscles

   object glass, object lens, objective, objective lens

   the lens or system of lenses in a telescope or microscope that is nearest the object being viewed

   Abbe condenser

   a condenser having 2 or 3 lenses with wide aperture for use in microscopes

   achromatic lens

   a compound lens system that forms an image free from chromatic aberration

   closeup lens

   a photographic lens with a short focal length used to take pictures at short ranges

   portrait lens

   a compound camera lens with a relatively high aperture

   sunglass

   a convex lens that focuses the rays of the sun; used to start a fire

   telephoto lens, zoom lens

   a camera lens that magnifies the image

   fisheye lens, wide-angle lens

   a camera lens having a wider than normal angle of view (and usually a short focal length); produces an image that is foreshortened in the center and increasingly distorted in the periphery

   type of:

   optical device

   a device for producing or controlling light
2. noun

   electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons
   synonyms: electron lens

   type of:

   electronic equipment, electronics

   equipment that involves the controlled conduction of electrons (especially in a gas or vacuum or semiconductor)
3. noun

   biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina
   synonyms: crystalline lens, lens of the eye

   type of:

   organ

   a fully differentiated structural and functional unit in an animal that is specialized for some particular function
4. noun

   (metaphor) a channel through which something can be seen or understood
   “the writer is the lens through which history can be seen”

   type of:

   channel, communication channel, line

   (often plural) a means of communication or access