# sensor

/ˈsɛnsɝ/ (US) · /sˈɛnsɐ/ (UK) · CEFR B1 · Noun

Source: https://englishreference.com/word/sensor
Updated: 2026-05-02

## Definition

a small electronic device that notices changes in things like heat, light, or movement. It sends this information to a computer or another machine to make it react.

For teachers: a device that detects or measures a physical property and records, indicates, or otherwise responds to it. It typically converts a physical stimulus into an electronic signal for processing.

## Examples

- The lights turn on automatically when the sensor detects movement.
- Modern cars use a proximity sensor to warn the driver if they are getting too close to another vehicle.
- The laboratory is equipped with a highly sensitive humidity sensor to ensure that the delicate chemical samples remain stable throughout the duration of the experiment.

## Usage notes

- Commonly used in compound nouns such as 'motion sensor', 'heat sensor', or 'oxygen sensor'.

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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.