# actuator

/ˈæktjuˌeɪtɝ/ (US) · /ˈæktʃuːˌeɪtɐ/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/actuator
Updated: 2026-05-26

## Definition

a part of a machine that moves or controls something else. It turns energy, like electricity or air pressure, into physical movement.

For teachers: a mechanical device for moving or controlling a system. It converts an input signal into some kind of motion or physical action, typically using energy from a source such as electricity, hydraulics, or pneumatics.

## Examples

- The robot uses a small actuator to move its arm.
- In modern cars, the fuel injection system relies on a precise actuator to open the valve at the right time.
- The engineering team replaced the hydraulic actuator with a more efficient electric version to reduce the overall weight and improve the vehicle's fuel economy.

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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.