sensor
n.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.”
Commonly used in compound nouns such as 'motion sensor', 'heat sensor', or 'oxygen sensor'.
Originated 1925–30, formed as a Latin loanword from sentiō (“to feel”) + -tor (“-er”). By surface analysis, sense + -or.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.