noun
kelvin
KEHL-vihn
noun
1
The base unit of temperature in the metric system, used mainly in science, where zero kelvin is absolute zero.
"Water freezes at 273.15 kelvin."
"Scientists measure the temperature of stars in kelvin."
2
A measurement of how warm or cool a light source looks, used to describe the color of light bulbs and camera settings.
"Warm white bulbs are usually rated around 2700 kelvin, while daylight bulbs run closer to 5000 kelvin."
How to Use Kelvin
Learner’s notesIn plain EnglishA unit for measuring temperature in science, and also used to describe the warmth or coolness of light.
Common mistake
Kelvin is capitalized as a name but the unit itself is written lowercase (kelvin), and it does not take a degree symbol the way Celsius or Fahrenheit do.
Common pairings
degrees kelvin (informal, technically just "kelvin")
color temperature in kelvin
Word Forms
kelvins plural
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Water freezes at 273.15 _____.
Etymology
Named after the Scottish physicist William Thomson, Lord Kelvin, who helped define the absolute temperature scale.