William Thomson, 1st Baron, 1824–1907, English physicist and mathematician.
(lowercase) the basic unit of temperature in the International System of Units (SI), formally defined to be approximately 1/273 of the triple point of water. K
Thermodynamics. noting or pertaining to an absolute scale of temperature Kelvin scale in which the degree intervals are equal to those of the Celsius scale and in which absolute zero is 0 degrees Kelvin and the triple point of water has the value of approximately 273 degrees Kelvin.
Also Kelwin a male given name.
The SI unit used to measure temperature, the basic unit of the Kelvin scale. A difference of one degree Kelvin corresponds to the same temperature difference as a difference of one degree Celsius.
See Table at measurement See also absolute zero
A kelvin is a unit for measuring temperature. The kelvin scale is based on absolute zero, the coldest possible measurement, so there is no such thing as a negative temperature in kelvins. The Celsius scale is based on kelvins, but the two scales differ in that kelvins measure an absolute temperature, based on a zero that can literally not get any colder. While temperature isn't commonly measured in kelvins outside the science lab, it's a vital way of calculating temperature for scientists. The kelvin is named after the Irish-Scottish physicist Sir William Thompson, also known as Lord Kelvin.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Andrew Kelvin, chief Canada strategist for TD Securities, said the return to growth and core inflation at or slightly above 2% should provide some comfort to central-bank policymakers.
From The Wall Street Journal ● Jul. 13, 2026
One of its key roles is monitoring warm ocean features known as Kelvin waves, which are closely linked to the development of El Niño.
From Science Daily ● Jun. 15, 2026
That allows the sea level to rise a little bit, “and it creates what we call a downwelling oceanic Kelvin wave,” said Jon Gottschalck, the Climate Prediction Center’s operational prediction branch chief.
From Los Angeles Times ● Jun. 15, 2026
The 31-year-old's run was more than one minute faster than the late Kelvin Kiptum's previous record of 2:00:35, which was set in 2023.
From BBC ● Apr. 29, 2026
The girl said again, “Crazy Kelvin, stop it. Just stop it.”
From "One Crazy Summer" by Rita Williams-Garcia
They reported a heat-to-electricity conversion efficiency exceeding 10% at a temperature difference of 475 kelvin, or about 855 degrees Fahrenheit.
From Science Daily ● May 16, 2024
More intriguingly, they determined that some of the PAHs had nuclei which could only have been formed in temperatures under 100 kelvin, which is extremely cold.
From Salon ● Dec. 22, 2023
Mr Scheidt notes that for warm-toned LEDs, the efficiency drops somewhat, but it's still possible to achieve around 160 lumens per watt for warm white luminaires, with a colour temperature of 2,700 kelvin.
From BBC ● Dec. 18, 2023
That star had a surface temperature of roughly 200,000 kelvin, with a stellar wind travelling outward at 16,000 kilometres per second — roughly 5% of the speed of light.
From Scientific American ● Feb. 1, 2023
When it decides there's too much oxygen, it starts collecting air in a tank and cooling it to 90 kelvin.
From "The Martian" by Andy Weir
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
