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

n a transparent optical device used to converge or diverge transmitted light and to form images

lens system, lense
show 23 types...
hide 23 types...
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
(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
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

n electronic equipment that uses a magnetic or electric field in order to focus a beam of electrons

electron lens
Type of:
electronic equipment
equipment that involves the controlled conduction of electrons (especially in a gas or vacuum or semiconductor)

n biconvex transparent body situated behind the iris in the eye; its role (along with the cornea) is to focuses light on the retina

crystalline lens, lens of the eye
Type of:
a fully differentiated structural and functional unit in an animal that is specialized for some particular function

n (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

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, Vocabulary.com can put you on the path to systematic vocabulary improvement.