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
The spacecraft will study Earth using synthetic aperture radar, gathering data at all times of day and in all weather conditions from an altitude of 385 miles (620 kilometers).
—
Mike Wall, Space.com, 3 Jan. 2026
Camera changes could include a variable aperture system.
—Aamir Khollam, Interesting Engineering, 1 Jan. 2026
School Grade Hobbies Currently satellites, synthetic aperture radar, and GPS are used to collect data on flood damage, track the location of victims, and communicate with emergency responders.
—Joanna Goodrich, IEEE Spectrum, 31 Dec. 2025
Max & Holly Stumble Upon Henry’s Traumatic Memory Out in the desert, where Holly draws the connection that the shape of the caves mimics the aperture in the spyglass, an M of sorts, she and Max literally almost fall down a mineshaft.
—Dessi Gomez, Deadline, 25 Dec. 2025
See All Example Sentences for aperture
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Mike Wall, Space.com, 3 Jan. 2026
Camera changes could include a variable aperture system.
—Aamir Khollam, Interesting Engineering, 1 Jan. 2026
School Grade Hobbies Currently satellites, synthetic aperture radar, and GPS are used to collect data on flood damage, track the location of victims, and communicate with emergency responders.
—Joanna Goodrich, IEEE Spectrum, 31 Dec. 2025
Max & Holly Stumble Upon Henry’s Traumatic Memory Out in the desert, where Holly draws the connection that the shape of the caves mimics the aperture in the spyglass, an M of sorts, she and Max literally almost fall down a mineshaft.
—Dessi Gomez, Deadline, 25 Dec. 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 5 Jan. 2026.
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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