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a·lu·mi·na

(ə-lmə-nə)

Any of several forms of aluminum oxide, Al₂O₃, occurring naturally as corundum, in a hydrated form in bauxite, and with various impurities as ruby, sapphire, and emery, used in aluminum production and in abrasives, refractories, ceramics, and electrical insulation. Also called aluminum oxide.

[New Latin alūmina, from Latin alūmen, alūmin-, alum.]

Indo-European & Semitic Roots Appendices

Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

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Semitic Roots

The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.

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