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kilowatt

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Etymology and origin of the English word kilowatt

Confidence
Established
Formation
Compound
First attested
1884 the journal Engineering More words from the 19th century
Ultimate origin
English kilo-,watt

Pronunciation

  • /ˈkɪ.ləˌwɒt/, /ˈkiə.ləˌwɒt/[1]

Etymology

It is formed from English kilo- + watt,[2][3][4][5][6] and Merriam-Webster classes it as International Scientific Vocabulary.[5][7] The prefix was introduced in French in 1795, when the metric system was adopted there, as an irregular reduction of Ancient Greek χίλιοι (khílioi, “a thousand”).[2][3] The unit watt, proposed and adopted in 1882, is named after the Scottish engineer James Watt (1736–1819).[3][2]

Earliest recorded meaning

A thousand watts: 1884, in the journal Engineering of 17 October,[2] the year that Barnhart, Etymonline and Merriam-Webster also give;[4][3][5] Dictionary.com dates the word to 1880–85.[6]

Semantic evolution

The word was at first also written kilo-watt.[3][1] The compound kilowatt-hour, a unit of energy equal to the work done by one kilowatt in one hour, is recorded from 1892,[8][3] and kilowattage, power expressed in kilowatts, also used figuratively, from 1935.[8]

Timeline

  • 1884 – a unit of power, a thousand watts, also written kilo-watt.[2][3][4][5]

Meanings

Noun

  1. A unit of power equal to 1,000 watts, or about 1.34 horsepower; symbol kW: The new heater draws two kilowatts.[5][9][2]

Word family

  • kilowatt-hour
  • watt
  • kilo-
  • megawatt

Usage notes

Wiktionary notes that kilowatt is sometimes used loosely for kilowatt-hour.[1]

References

  1. ^ a b c Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  4. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  5. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  6. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
  7. ^ Gove, Philip Babcock, ed. (1961), Webster's Third New International Dictionary of the English Language, Unabridged, Springfield, Mass.: G. & C. Merriam
  8. ^ a b Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
  9. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
Cite this entry

“Kilowatt.” Etymologically, 13 Nov. 2026, etymologically.com/en/kilowatt. Accessed 13 Nov. 2026.

Last edited on . ·