CORUNDUM

corundom, corundum

(noun) very hard mineral used as an abrasive

Source: WordNet® 3.1


Etymology

Noun

corundum (countable and uncountable, plural corundums)

(mineral) An extremely hard mineral, a form of aluminum oxide with the chemical formula Al2O3, that occurs in the form of the gemstones sapphire and ruby; it is used as an abrasive.

Source: Wiktionary


Co*run"dum (k-rn"dm), n.; pl. Corundums (-d. [Also corindon.] Etym: [From Hind. kurand corundum stone.] (Min.)

Definition: The earth alumina, as found native in a crystalline state, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.

Note: The name corundum is sometimes restricted to the non- transparent or coarser kinds. Emery is a dark-colored granular variety, usually admixed with magnetic iron ore.

Source: Webster’s Unabridged Dictionary 1913 Edition



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Word of the Day

18 April 2025

GROIN

(noun) the crease at the junction of the inner part of the thigh with the trunk together with the adjacent region and often including the external genitals


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Coffee Trivia

In the 18th century, the Swedish government made coffee and its paraphernalia (including cups and dishes) illegal for its supposed ties to rebellious sentiment.

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