aperture
Americannoun
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an opening, as a hole, slit, crack, gap, etc.
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Also called aperture stop. Optics. an opening, usually circular, that limits the quantity of light that can enter an optical instrument.
noun
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a hole, gap, crack, slit, or other opening
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physics
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a usually circular and often variable opening in an optical instrument or device that controls the quantity of radiation entering or leaving it
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the diameter of such an opening See also relative aperture
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Other Word Forms
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.
Vocabulary lists containing aperture
"The Cask Of Amontillado" by Edgar Allan Poe
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The Curious Incident of the Dog in the Night-Time
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50 Great Words from The Curious Incident of the Dog in the Night-Time, by Mark Haddon
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Styles also topped this week's singles chart with American Girls, with two further songs in the top five - Aperture at number four and Ready, Steady, Go! at five.
From BBC • Mar. 13, 2026
Earlier, Harry Styles had opened the night with a performance of his new single "Aperture", ahead of the much-anticipated release of his new album next Friday.
From Barron's • Feb. 28, 2026
From 1990 to 1992, NASA's Magellan spacecraft mapped Venus using a Synthetic Aperture Radar system.
From Science Daily • Feb. 12, 2026
BBC Verify made this assessment through analysis of optical and Synthetic Aperture Radar satellite imagery captured over Isfahan on Friday.
From BBC • Apr. 20, 2024
Aperture narrow, linear, above angulated, below a little contracted.
From Zoological Illustrations, Volume I or Original Figures and Descriptions of New, Rare, or Interesting Animals by Swainson, William
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
