What does thermostat mean?
A thermostat is a device that maintains a selected temperature by controlling heating or cooling equipment. It typically includes a sensor that detects the surrounding temperature and switches a furnace, boiler, air conditioner, refrigerator, or other system on or off as needed. The word is common in discussions of homes, vehicles, appliances, and industrial equipment: people adjust the thermostat, raise or lower its setting, or check whether it is working properly. Although a thermostat contains temperature-sensing technology, it differs from a thermometer because its main function is control rather than measurement. The term is also used for the control itself in older or mechanical systems. Overall, thermostat describes a practical piece of technology that translates a desired temperature into automatic operation, making it a familiar and useful word in both everyday and technical language.
nounA thermostat is a device that automatically controls the temperature of a room, vehicle, appliance, or other system by switching heating or cooling equipment on and off. It usually contains a temperature sensor and a mechanism for maintaining a selected setting.
- A device that automatically controls the temperature of a room, vehicle, appliance, or other system by activating or deactivating heating or cooling equipment.
"She turned the thermostat up before the guests arrived."
"The thermostat automatically lowers the temperature when the house is empty."
"Check the thermostat settings before adjusting the heating system."
The regular plural is used when referring to multiple thermostats or to thermostat devices generally.
"The thermostats in the hotel rooms are programmed to reduce energy use at night."
A thermostat is a thermometer with ambition: it measures the temperature, then tells the heating or cooling system what to do about it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does thermostat come from?
Thermostat was formed in the 19th century from the combining form thermo-, associated with Greek thermē, “heat,” and the element -stat, linked to Greek statos, “standing” or “set.” The name reflects the device’s role as a temperature-setting and regulating mechanism. Its relatives include thermometer, thermal, thermoscope, and isotherm, all of which draw on the same Greek root for heat.
Related word forms
How thermostat is actually used
Thermostat is a neutral, standard noun used in everyday speech and technical contexts. In British English, the device is especially associated with central heating, while in American English it is also commonly used for vehicle climate controls, refrigerators, and air-conditioning systems.
Easily confused with thermostat
A thermometer measures and displays temperature, whereas a thermostat uses temperature information to control heating or cooling equipment.