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

Selfies snapped with the Reno 13 Pro are sharper and more detailed than most other selfie cameras, with even a bit of natural bokeh due to the fast-ish aperture. —Ben Sin, Forbes, 3 Jan. 2025

The retrograde minutes are indicated by a large central hand, while the hours are in an aperture at 12 o‘clock, and the small seconds are displayed using a red and white disc. —Sophie Furley, Robb Report, 24 Dec. 2024

In this mode, the ZV-1 II will detect when another face comes into the scene and automatically stops down the aperture to keep everyone in focus. —Simon Hill, WIRED, 30 Nov. 2024

Open the aperture beyond ROI, and leverage the return on experience (ROX) framework shared in my previous article to create a rather holistic set of metrics. —Sujay Saha, Forbes, 18 Dec. 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