Definition of kelvin in US English:


(also K)


  • The SI base unit of thermodynamic temperature, equal in magnitude to the degree Celsius.

    • ‘To the scientists' surprise, tests showed that the resulting compound is a superconductor at cryogenic temperatures below 18.5 kelvins.’
    • ‘The temperature of the lava, about 1,500 kelvins, is similar to that of the hottest volcanoes on Earth.’
    • ‘Astronomers haven't been able to explain why the center of Perseus and other galaxy clusters are as hot as 50 million kelvins, even though the gas there radiates energy away and should therefore be cold.’
    • ‘During typical sonoluminescence experiments, spectral emission temperatures range up to tens of thousands of kelvins, and the rapidly imploding bubble walls can generate internal shock waves under certain conditions.’
    • ‘Liquid helium will cool the gyroscopes to 1.8 kelvins.’


Late 19th century: named after Lord Kelvin (see Kelvin, 1st Baron).