potassium

Etymology

It is formed from English potass + -ium,^[2][3][4] coined by the English chemist Sir Humphry Davy, who first isolated the element from potash.^[5][6][7] Barnhart and Etymonline take the base as New Latin potassa, a Latinized form of potash, recorded in English as potass from 1799;^[8][6][5] the Shorter Oxford allows either potash or potass.^[9] Potass is borrowed from French potasse,^[4][3] which, like potassa, is a loan from Germanic;^[5] the OED records French potasse from 1690 and Middle French pottas from 1577.^[2] The source is Dutch potasch, earlier pot-asschen, literally "pot ashes", recorded in Kiliaan in 1588,^[2][3][5] from pot (“pot”) and as (“ash”).^[10] The OED compares the earlier New Latin potassinum, used in 1784 by the Swedish chemist Torbern Bergman in his Latin nomenclature of minerals, and notes that potassium (1808) was taken from English.^[2] The chemical symbol K stands for New Latin kalium (“potash”), ultimately from an Arabic word for burnt ashes; see alkali.^[5][11]

Earliest recorded meaning

The soft, light, silvery-white metallic element of the alkali metal group: 1807, in Davy's paper in the Philosophical Transactions of the Royal Society.^[2][6]

Semantic evolution

The name records how the element was found.^[11][6] Potash, an impure potassium carbonate, was made by burning plant material, soaking the ashes in water and boiling the solution down in large iron pots; it was used to make soap and glass.^[11][5] Davy separated the metal from potash in 1807 and named it after its source.^[6][3] Hoad notes that Davy also gave the Latin form potassa to potassium monoxide.^[3] From 1865 the word appears in the names of compounds such as potassium carbonate,^[12] and since 1953 in potassium-argon dating, which estimates the age of minerals from the proportion of potassium-40 to argon-40.^[12][13]

Timeline

• 1577 – Middle French pottas, potash.^[2]
• 1588 – Dutch pot-asschen, recorded in Kiliaan.^[2]
• 1784 – Latin potassinum in Bergman's mineral nomenclature.^[2]
• 1799 – potass in English.^[6]
• 1807 – potassium, coined by Davy.^[2][6][5]
• 1808 – French potassium, from English.^[2]
• 1865 – in names of compounds, as potassium carbonate.^[12]
• 1953 – potassium-argon dating.^[12]

Meanings

Noun

1. A soft, light, silvery-white, highly reactive metallic chemical element of the alkali metal group, atomic number 19, symbol K, which oxidizes rapidly in air and reacts violently with water.^[14][15][2]
2. Its compounds are widely used, especially in fertilizers, and its salts are essential to living things.^[15][9]

Word family

• potassic

Related words

• potash
• potass
• potassa
• pot
• ash
• alkali
• sodium

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
4. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
5. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
7. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
9. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
10. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
11. ^ a b c Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press
12. ^ a b c d Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
13. ^ Soanes, Catherine; Stevenson, Angus, eds. (2004), Concise Oxford English Dictionary, 11th ed., Oxford: Oxford University Press
14. ^ Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
15. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins