thermostatPronunciation: /ˈθəːməstat/Translate thermostat | into French | into German | into Italian | into Spanish Definition of thermostat noun a device that automatically regulates temperature, or that activates a device when the temperature reaches a certain point. Derivatives thermostaticPronunciation: /-ˈstatɪk/ adjective thermostaticallyPronunciation: /-ˈstatɪk(ə)li/ adverb thermostat in other Oxford dictionaries Definition of thermostat in the US English dictionary