alumina

American  

[uh-loo-muh-nuh] / əˈlu mə nə /

noun

1. the natural or synthetic oxide of aluminum, Al 2 O 3 , occurring in nature in a pure crystal form as corundum.

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alumina British  

/ əˈluːmɪnə /

noun

1. another name for aluminium oxide

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alumina Scientific  

/ ə-lo̅o̅′mə-nə /

1. Any of several forms of aluminum oxide used in aluminum production and in abrasives, refractories, ceramics, and electrical insulation. Alumina occurs naturally as the mineral corundum and, with minor traces of chromium and cobalt, as the minerals ruby and sapphire, respectively. In its hydrated form it also occurs as the rock bauxite. Also called aluminum oxide. Chemical formula: Al ₂ O ₃ .

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Etymology

Origin of alumina

1780–90; < Latin alūmin-, stem of alūmen alum ¹ + -a ⁴

Compare meaning

How does alumina compare to similar and commonly confused words? Explore the most common comparisons:

• alumina vs. aluminum

Example Sentences

When overseas aluminum smelters shut down, it can hurt Alcoa’s business, because it reduces demand for raw alumina.

From Barron's • Mar. 30, 2026

Morgan analyst William Peterson wrote in a recent note to clients that roughly a third of Alcoa’s alumina capacity is contracted to “key players” in the Middle East, including EGA and Alba.

From MarketWatch • Mar. 30, 2026

Alcoa ships some alumina to the Middle East.

From Barron's • Mar. 30, 2026

The Middle East accounts for about 8%-9% of global aluminum output, but produces only around 3% of global alumina and around 1% of bauxite, leaving smelters highly dependent on seaborne imports, according to market watchers.

From The Wall Street Journal • Mar. 19, 2026

Aluminium and oxygen form alumina, of which are constituted the sapphire, the ruby and other precious stones, but alumina is most commonly found in combination with silica, or silicon and oxygen.

From Marvels of Scientific Invention An Interesting Account in Non-technical Language of the Invention of Guns, Torpedoes, Submarine Mines, Up-to-date Smelting, Freezing, Colour Photography, and many other recent Discoveries of Science by Corbin, Thomas W.