aperture
noun
ap·er·ture
ˈa-pər-ˌchu̇r 
ˈa-pə-,
-chər,
-ˌtyu̇r,
-ˌtu̇r
1
: an opening or open space : hole
entered the cave through a narrow aperture
2
a
: the opening in a photographic lens that admits the light
b
: the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument
c
: the diameter of the objective lens or mirror of a telescope
Examples of aperture in a Sentence
We entered the cave through a narrow aperture.
The photograph was taken using a fast shutter speed and a large aperture.
Recent Examples on the Web
That's good news as purple and green longitudinal chromatic aberration that's often visible with bright aperture lenses is all but impossible to remove with software, black-and-white conversions aside.
—
PC Magazine, 17 Apr. 2025
And get an even closer look thanks to the 8 times digital zoom and 24mm objective aperture that offers a broader field of vision.
—New Atlas, 10 Mar. 2025
The lens includes a manual focus ring, an aperture control ring, and nothing else.
—PCMAG, 5 Mar. 2025
This visor-like shade serves as a deployable aperture cover, blocking stray light that could interfere with observations or reduce the sensitivity of the infrared telescope, which is expected to launch no later than 2027.
—Victoria Corless, Space.com, 24 Feb. 2025
See All Example Sentences for aperture
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PC Magazine, 17 Apr. 2025
And get an even closer look thanks to the 8 times digital zoom and 24mm objective aperture that offers a broader field of vision.
—New Atlas, 10 Mar. 2025
The lens includes a manual focus ring, an aperture control ring, and nothing else.
—PCMAG, 5 Mar. 2025
This visor-like shade serves as a deployable aperture cover, blocking stray light that could interfere with observations or reduce the sensitivity of the infrared telescope, which is expected to launch no later than 2027.
—Victoria Corless, Space.com, 24 Feb. 2025
See All Example Sentences for aperture
Cite this Entry
“Aperture.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/aperture. Accessed 29 Apr. 2025.
Copy CitationKids Definition
aperture
noun
ap·er·ture
ˈap-ə(r)-ˌchu̇(ə)r
-chər
1
: an opening or open space : hole
2
a
: the opening in a camera lens that allows light through
b
: the diameter of the opening in a camera lens
Medical Definition
aperture
noun
ap·er·ture
ˈap-ə(r)-ˌchu̇(ə)r, -chər, -ˌt(y)u̇(ə)r
1
: an opening or open space
2
: the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument
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