thermostat

American  

[thur-muh-stat] / ˈθɜr məˌstæt /

noun

thermostats plural

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

Derived Forms

• thermostatic
  adjective
• thermostatically
  adverb

Inflected Forms

Nouns

• thermostats
  plural

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

On Thursday, Chicago utility company ComEd said its power grid was under "critical strain," and urged residents to "raise your thermostat as high as is comfortably safe."

From Barron's • Jul. 3, 2026

"Raise your thermostat as high as is comfortably safe," the company urged, while calling on residents to delay using laundry, dishwashers and electric vehicle chargers until after 8:00 pm.

From Barron's • Jul. 1, 2026

Deploy fans: Ceiling fans create a wind-chill effect that makes a room feel several degrees cooler, allowing you to set the thermostat higher.

From MarketWatch • Jun. 29, 2026

Gavin says he's happy to have the house at 19C or 20C but his wife sometimes turns up the thermostat to 23C.

From BBC • Apr. 15, 2026

It had a thermostat made of bimetal, which was two different metals attached to each other.

From "A Place to Belong" by Cynthia Kadohata

Related Words

• manager