cation

Etymology

It is borrowed from Ancient Greek κατιόν (katión, “(a thing) going down”),^[2][3][4][5] the neuter of the present participle of κάτειμι (káteimi, “to go down”),^[2][3][6][7] from κατά (katá, “down”) and εἶμι (eîmi, “to go”),^[2][6][4] from Proto-Indo-European *ei- (“to go”).^[4][6] The Greek verb of going is related to Latin eō (“to go”).^[7] The word was proposed by William Whewell and published by Michael Faraday in 1834,^[4] and it is related to anion and ion.^[8][7] Some dictionaries analyse it instead as cata- or cathode with ion.^[9][10][11]

Earliest recorded meaning

An ion carrying a positive charge, which moves towards the cathode in electrolysis: 1834, in Faraday's Experimental Researches in Electricity.^[2][3][4]

Semantic evolution

The name describes the ion "going down" to the cathode, to which Barnhart, Klein and Hoad refer for the sense.^[8][7][12] The word has kept its sense; the adjective cationic was added in the early 20th century.^[9]

Timeline

• 1834 – a positively charged ion, moving to the cathode in electrolysis.^[2][3][4]

Meanings

Noun

1. A positively charged ion, such as an ion of hydrogen or calcium; opposed to anion.^[5][11][2]
2. The ion in a solution undergoing electrolysis that moves to the cathode.^[5][11][2]

Word family

• cationic
• cationically
• cation exchange

Related words

• anion
• ion
• cathode
• anode
• exit

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
4. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ a b c d Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
8. ^ a b Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
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. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
11. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
12. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press