English Reference
noun · verb

lens

n. · v.
US /ˈɫɛnz/ lens UK spelling lens's, lenses

  1. 01 B2 Upper Intermediate

    n.a curved piece of glass or plastic used in glasses, cameras, or telescopes to make things look clearer or larger.

    n.a transparent optical device, typically made of glass or plastic, that focuses or disperses light through refraction.

    Simple

    He cleaned his camera lens carefully before taking a photo of the mountains.

    In context

    The optometrist determined that a stronger corrective lens was necessary to compensate for the patient's worsening astigmatism.

  2. 02 C1 Advanced Technical Anatomy

    n.the clear part inside your eye that helps you focus on what you are looking at.

    n.the transparent, biconvex structure behind the iris that changes shape to focus light onto the retina.

    Simple

    As people get older, the lens in the eye can become less flexible.

    In context

    Cataract surgery involves the removal of the clouded natural lens and the insertion of a clear artificial substitute.

    crystalline lens
  3. 03 C1 Advanced Academic

    n.a particular way of seeing or thinking about a situation.

    n.a figurative perspective or conceptual framework through which a subject is analysed or perceived.

    Simple

    We should look at this problem through the lens of social justice.

    In context

    The historian examined the industrial revolution through the lens of environmental impact rather than purely economic growth.

  4. 04 C2 Proficiency Technical Computing

    n.a tool in some computer languages used to look at or change data inside a complex structure.

    n.a functional programming construct used to access and update nested data structures in a composable way.

    Simple

    The developer used a lens to update the user's address deep inside the database object.

    In context

    By using lenses, the programmer could modify deeply nested state properties without manually destructuring the entire immutable object tree.

    functional reference
  5. 05 C2 Proficiency Technical Theatre

    v.to record or shoot a movie.

    v.to film or photograph a motion picture or scene.

    Simple

    The director decided to lens the entire movie in black and white.

    In context

    The production was lensed on location in Iceland to take advantage of the unique natural light and dramatic landscapes.

That third lens on the back is actually a window for a time-of-flight sensor that helps with focus.

Ars Technica· 4 Sept 2026

It says you can recycle the cardboard frames so long as you separate them from the lenses, which are harder to recycle.

BBC News· 13 Aug 2026

Borrowed from Latin lēns (“lentil”), with Medieval Latin later taking on the sense of “lens”, a semantic loan from Arabic عَدْسَة (ʕadsa, “lentil; optic lens”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin Latin lēns
Level B2 · Upper Intermediate
Frequency Common
Updated