lens

American  

[lenz] / lɛnz /

noun

plural

lenses

1. a piece of transparent substance, usually glass, having two opposite surfaces either both curved or one curved and one plane, used in an optical device in changing the convergence of light rays, as for magnification, or in correcting defects of vision.

2. a combination of such pieces.

3. some analogous device, as for affecting sound waves, electromagnetic radiation, or streams of electrons.

4. Anatomy. crystalline lens.

5. Geology. a body of rock or ore that is thick in the middle and thinner toward the edges, similar in shape to a biconvex lens.

---

verb (used with object)

1. Movies. to film (a motion picture).

lens ¹ British  

/ lɛnz /

noun

1. a piece of glass or other transparent material, used to converge or diverge transmitted light and form optical images

2. Also called: compound lens.  a combination of such lenses for forming images or concentrating a beam of light

3. a device that diverges or converges a beam of electromagnetic radiation, sound, or particles See electron lens

4. anatomy See crystalline lens

---

Lens ² British  

/ lɑ̃, lenz /

noun

1. an industrial town in N France, in the Pas de Calais department; badly damaged in both World Wars. Pop: 36 206 (1999)

---

lens Scientific  

/ lĕnz /

1. A transparent structure behind the iris of the eye that focuses light entering the eye on the retina.

2. 1. A piece of glass or plastic shaped so as to focus or spread light rays that pass through it, often for the purpose of forming an image.

   2. A combination of two or more such lenses, as in a camera or telescope.

3. A device that causes radiation to converge or diverge by an action analogous to that of an optical lens. The system of electric fields used to focus electron beams in electron microscopes is an example of a lens.

---

lens ¹ Cultural  

1. A piece of transparent material, such as glass, that forms an image from the rays of light passing through it. (See focal length, refraction, and telescope.)

---

lens ² Cultural  

1. A clear, almost spherical structure located just behind the pupil of the eye. The lens focuses waves of light on the retina.

---

Other Word Forms

• lensless adjective
• lenslike adjective
• unlensed adjective

Etymology

Origin of lens

First recorded in 1685–95; from New Latin, special use of Latin lēns “a lentil” (from its shape); lentil

Explanation

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.

Example Sentences

It’s amusing to look at your life through an AI’s lens.

From The Wall Street Journal • Apr. 11, 2026

I’ve written previously that there are three ways to view the war: the American strategic-imperative lens, the Israeli security lens and the Iranian national-preservation lens.

From MarketWatch • Apr. 9, 2026

“English” insists on viewing its Iranian characters through a humane, rather than geopolitical, lens.

From Los Angeles Times • Apr. 8, 2026

Looking back at past stock picks offers a useful lens into how market conditions evolve over time.

From Barron's • Apr. 8, 2026

A marvel of miniature engineering, the T-50 had a lens only four millimeters wide.

From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau

Related Words

• glass