corundum

Etymology

It is borrowed from Tamil குருந்தம் (kuruntam, “ruby, sapphire”),^[2][3][4][1] which the OED, Hoad and Weekley spell kurundam;^[2][5][6] Barnhart and Etymonline say that it came into English through Anglo-Indian use.^[7][8] The Oxford Dictionary of English and the Shorter Oxford also name a Telugu form beside the Tamil one, and the OED adds a Hindi word for kinds of sapphire.^[9][4][2][7] The Tamil word is related to Sanskrit कुरुविन्द (kuruvinda, “ruby”),^{[2][5][10][7]} from which Klein, Partridge and Merriam-Webster Unabridged derive it;^[11][12][13] Etymonline and Klein call the Sanskrit word of unknown or uncertain origin.^[8][11]

Earliest recorded meaning

A hard mineral of the same species as sapphire and ruby, but opaque or only translucent: 1728, in J. Woodward's catalogue of foreign fossils.^[2][8] Barnhart dates it to before 1728,^[7] and Merriam-Webster Unabridged gives 1804 as its first known use.^[13]

Semantic evolution

The word was first used for the dull, opaque stones that, unlike their transparent relatives, were valued for grinding and polishing other gems and steel.^[2][8] In 1804 mineralogists began to use it as the name of the whole mineral species, so that it came to include the transparent sapphire and ruby themselves;^[2][13] the Shorter Oxford and Collins now define it chemically, as aluminium oxide, whose red variety is ruby and blue variety sapphire.^[4][14] From 1792 it was used attributively for tools and wheels used in polishing and in dressing millstones,^[2] and it is now also made synthetically for abrasives, refractories and bearings.^[4][13]

Timeline

• 1728 – an opaque mineral of the sapphire and ruby species.^[2][8]
• 1792 – attributive, as in corundum wheel, for polishing tools.^[2]
• 1804 – in mineralogy, the name of the whole species, including sapphire and ruby.^[2][13]

Meanings

Noun

1. A very hard mineral, crystalline aluminium oxide, found in many colours; its transparent varieties include the ruby and the sapphire.^[14][13][4]
2. This mineral in an opaque or synthetic form, used as an abrasive and in refractory materials and bearings: a corundum grinding wheel.^[4][13][14]

Word family

• alundum
• carborundum

References

1. ^ a b 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. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e f Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
7. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
9. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
10. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
11. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
12. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
13. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
14. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins