aperture

American  

[ap-er-cher] / ˈæp ər tʃər /

noun

• apertures
  plural

1. an opening, as a hole, slit, crack, gap, etc.

2. Also called aperture stop.  Optics. an opening, usually circular, that limits the quantity of light that can enter an optical instrument.

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aperture British  

/ ˈæpətʃə /

noun

1. a hole, gap, crack, slit, or other opening

2. physics

   1. a usually circular and often variable opening in an optical instrument or device that controls the quantity of radiation entering or leaving it

   2. the diameter of such an opening See also relative aperture

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Other Word Forms

Derived Forms

• apertural
  adjective
• apertured
  adjective

Inflected Forms

Nouns

• apertures
  plural

Etymology

Origin of aperture

1400–50; late Middle English < Latin apertūra an opening, equivalent to apert ( us ) opened (past participle of aperīre; aper ( i )- ( see aperient) + -tus past participle suffix) + -ūra -ure

Explanation

An aperture is an opening, usually a small one. “If you can thread the silk through that aperture and pull it out the other side, we can knot it and create a loop.” The most common place you’ll find aperture is when you’re talking about cameras or photography. In that case, an aperture refers specifically to the hole or opening in the lens that lets light through, which you can adjust (with the f-stop) to let in more or less light, resulting in a shallow or deep range of focus. A large aperture means only one tiny point of the photo will be in sharp focus, while a small aperture means that much of the background as well as the foreground will be in focus.

Example Sentences

See Examples For:

aperture apertures

But there was, indeed, a brief aperture of time in the pressure cooker of 2020 when it all seemed possible.

From Slate ● Aug. 17, 2026

Synthetic aperture radar operates by transmitting microwave pulses from a moving satellite or aircraft toward Earth's surface and then combining the returning signals into detailed images.

From Science Daily ● Jun. 12, 2026

Cyclists completing the Whitehaven to Sunderland route are greeted with a view of Roker Lighthouse through an aperture, carved into a six-and-a-half-tonne slab of black granite.

From BBC ● Apr. 24, 2026

He brought out Kehlani for “Folded,” another perfectly regal ballad that revels in a small aperture.

From Los Angeles Times ● Apr. 13, 2026

The aperture was so screened and narrow, that curtain or shutter had been deemed unnecessary; and when I stooped down and put aside the spray of foliage shooting over it, I could see all within.

From "Jane Eyre" by Charlotte Brontë

To open it up to the street, the architects chose the motif of “frames, apertures and doorways.”

From The Wall Street Journal ● Dec. 17, 2025

Fractions of a second count and he can change apertures and focuses with a flick of his finger without taking his eyes from his quarry.

From BBC ● Aug. 4, 2024

Multi-layer soft materials first generate a rough mechanical conformation to the substrate, reducing leaking apertures to just micrometres.

From Science Daily ● Apr. 18, 2024

When they did, these apertures warped the doughnut shape or caused the ring to wobble, the team reported.

From New York Times ● Mar. 21, 2023

At the far end was the stone wall of the corrals, with apertures in the stone that were like loopholes running all along the face of each corral.

From "The Sun Also Rises" by Ernest Hemingway