aperture

noun

ap·er·ture ˈa-pər-ˌchu̇r

ˈa-pə-,

-chər,

-ˌtyu̇r,

-ˌtu̇r

Synonyms of aperture

: an opening or open space : hole

entered the cave through a narrow aperture

: the opening in a photographic lens that admits the light

: the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument

: 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

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.

These spacecraft — which are named after a widespread genus of owl — use synthetic aperture radar (SAR) to study our planet both day and night, and in all weather conditions. — Mike Wall, Space.com, 31 Aug. 2026 The first step was InSAR (interferometric synthetic aperture radar). — Rupendra Brahambhatt, Interesting Engineering, 29 Aug. 2026 The devices will feature faster chips, better battery life and major camera improvements, including a mechanical aperture on at least the larger model. — Bloomberg, Mercury News, 27 Aug. 2026 The GoPro only works with fully mechanical lenses that support manual aperture and focus control. — Jim Fisher, PC Magazine, 26 Aug. 2026 See All Example Sentences for aperture

Word History

Etymology

Middle English, borrowed from Latin apertūra, from apertus, past participle of aperīre "to open" + -ūra -ure — more at aperient

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler

The first known use of aperture was in the 15th century

See more words from the same century

Cite this Entry

Style

“Aperture.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/aperture. Accessed 3 Sep. 2026.

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Kids Definition

aperture

noun

ap·er·ture ˈap-ə(r)-ˌchu̇(ə)r

-chər

: an opening or open space : hole

: the opening in a camera lens that allows light through

: 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

: an opening or open space

: the diameter of the stop in an optical system that determines the diameter of the bundle of rays traversing the instrument

aperture

noun

Synonyms of aperture

Examples of aperture in a Sentence

Word History

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Cite this Entry

Kids Definition

Medical Definition

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