thermostat

American  

[thur-muh-stat] / ˈθɜr məˌstæt /

noun

1. a device, including a relay actuated by thermal conduction or convection, that functions to establish and maintain a desired temperature automatically or signals a change in temperature for manual adjustment.

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verb (used with object)

thermostatted, thermostated, thermostatting, thermostating

1. to equip or control with a thermostat.

thermostat British  

/ ˈθɜːməˌstæt /

noun

1. a device that maintains a system at a constant temperature. It often consists of a bimetallic strip that bends as it expands and contracts with temperature, thus breaking and making contact with an electrical power supply

2. a similar device that actuates equipment, such as a sprinkler, when a certain temperature is reached

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thermostat Scientific  

/ thûr′mə-stăt′ /

1. A device that automatically controls heating or cooling equipment in such a way as to maintain a temperature at a constant level or within a specified range, generally using a thermometer capable of triggering electrical switches that activate or deactivate the equipment.

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thermostat Cultural  

1. A device that monitors and automatically responds to changes in temperature and activates switches controlling devices such as furnaces or air conditioners.

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Other Word Forms

• thermostatic
  adjective
• thermostatically
  adverb

Etymology

Origin of thermostat

First recorded in 1825–35; thermo- + -stat

Explanation

If your house is always too cold in the winter, you might need to adjust the thermostat, or the dial that controls the indoor temperature. Most devices that emit heat have a thermostat, which controls how hot or cold things get. Car engines, electric blankets, furnaces, and ovens are all equipped with thermostats so that people can change the temperature, or in the case of cars, so that the car itself can keep the engine at the ideal temperature. The noun thermostat comes from the Greek word for heat, thermos, plus statos, or "a standing."

Example Sentences

As the child of penny-pinching Sicilian parents, I’m all too familiar with the dread surrounding the thermostat come midwinter.

From The Wall Street Journal • Jan. 23, 2026

Money saving is already ingrained at home, with batch cooking, more prudent selections on the thermostat, and warming the body rather than the whole home having become the norm for many people.

From BBC • Jan. 23, 2026

“That doesn’t look like it’ll go away anytime soon. People are going to be heavy on the thermostat for a good two weeks,” he said.

From MarketWatch • Jan. 22, 2026

Madeline Marchiano realizes that this winter’s runaway heating prices mean she can’t afford to raise her thermostat enough to warm her entire South Philadelphia rowhouse.

From Barron's • Jan. 22, 2026

The thermostat was turned all the way up and the furnace was banging and sounding like it was about to blow up but it still felt like Jack Frost had moved in with us.

From "The Watsons Go to Birmingham" by Christopher Paul Curtis

Related Words

• manager