Definition of alumina in US English:



  • A white solid, aluminum oxide, that occurs in bauxite and is found in crystalline form as the main constituent of corundum, sapphire, and other minerals.

    Aluminum oxide; chemical formula: Al₂O₃

    • ‘The metals are dispersed as tiny particles on a supporting framework of porous aluminium oxide.’
    • ‘Already some sites yield little more than a mass of crystallised aluminium oxide.’
    • ‘The silica, alumina, and iron come from sand, clay, and iron ore.’
    • ‘He derived the name from the mineral called alumina, which itself had only been named in English by the chemist Joseph Black in 1790.’
    • ‘The major exports are bauxite, alumina, gold, and diamonds.’


Late 18th century: from Latin alumen (see alum), on the pattern of words such as magnesia.