- the natural or synthetic oxide of aluminum, Al2O3, occurring in nature in a pure crystal form as corundum.
Origin of alumina
Also called aluminum oxide.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for alumina
It is composed of silica, alumina, carbonate of lime, magnesia and oxide of iron.Museum of Antiquity
L. W. Yaggy
It usually contains a little silica, alumina, and oxide of iron.
The affinity of alumina for the colouring matter is very remarkable.
At the end of this time it must be washed, to extract the sulphate of alumina.
The alumina may be separated from the ferric oxide by potash-lye.
- another name for aluminium oxide
C18: from New Latin, plural of Latin alūmen alum
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
- 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: Al2O3.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.