sensor
n. countablen. 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.
n. 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.
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.
Originated 1925–30, formed as a Latin loanword from sentiō (“to feel”) + -tor (“-er”). By surface analysis, sense + -or.
Commonly used in compound nouns such as 'motion sensor', 'heat sensor', or 'oxygen sensor'.