# aperture

/ˈæpɝtʃɝ/ (US) · /ˈæpətʃɐ/ (UK)

Source: https://englishreference.com/word/aperture
Updated: 2026-08-08

## Senses

### 1. camera/optics

noun · CEFR B2 · Technical

the opening in a camera lens that you can make wider or narrower to control the amount of light.

For teachers: the variable opening in an optical system, such as a camera lens, that determines the amount of light admitted to the focal plane.

- If you use a wider aperture, your photos will have a blurry background.
- The photographer adjusted the aperture to f/2.8 to achieve a shallow depth of field for the portrait session.

Usage: Often used with the verbs 'widen', 'narrow', or 'adjust'.

### 2. a physical gap

noun · CEFR C1 · Formal

a small or narrow hole, gap, or opening in a surface.

For teachers: a physical opening, hole, or gap through which light or matter may pass.

- A tiny aperture in the wall allowed a thin beam of light into the dark cave.
- The researchers measured the precise dimensions of the aperture to ensure the gas could flow through the valve at a constant rate.

Usage: Commonly used in technical or scientific descriptions of structures.

### 3. satellite antenna

noun · CEFR C2 · Technical

the large dish or part of a satellite that sends and receives radio signals.

For teachers: the effective area of an antenna that receives or transmits radio frequency energy.

- The satellite's large aperture allows it to send data across the ocean.
- Engineers designed a synthetic aperture radar to provide high-resolution imagery regardless of weather conditions or time of day.

## Examples

- A wide aperture lets in more light.
- She opened the aperture to capture the dimly lit stage performance.
- The photographer widened the aperture to blur the background, creating a soft, dreamlike effect around the subject.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.