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

Synonyms

• hole
• opening
• orifice
• perforation

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 not to say that goes away, but there’s been a widening of the aperture. —Brent Lang, Variety, 7 May 2024

The aperture control ring is part of the lens barrel, while the dual-purpose shutter/ISO dial and a dedicated EV compensation control are on the top plate. —PCMAG, 30 Apr. 2024

The aperture doesn't close down smaller than f/16 in this instance. —PCMAG, 20 Apr. 2024

For each higher-order mode, the laser effectively operates as a combination of smaller emitters whose narrower apertures cause the beam to diverge rapidly. —Susumu Noda, IEEE Spectrum, 14 Apr. 2024

There’s also a floating telephoto lens with an f/1.8 aperture that offers 3.2x optical zoom, and a periscope telephoto lens with an f/2.5 aperture that offers 5x optical zoom. —Julian Chokkattu Simon Hill, WIRED, 26 Feb. 2024

To calculate the correct power for a scene, divide the Guide Number by the aperture value. —PCMAG, 11 Apr. 2024

So the split between the United States and Israel that is obvious over Rafah in the moment, imminent over Lebanon for the spring and summer, and seemingly irreconcilable over annexation versus Palestinian independence in the long term becomes all the more cavernous as the aperture widens. —Hussein Ibish, The Atlantic, 5 Apr. 2024

The Harlem Renaissance reshaped the landscape of American culture, and for Black artists around the globe the aperture of what was possible widened. Invite your friends. —Veronica Chambers, New York Times, 5 Apr. 2024

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

Kids 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