aluminium hydroxide n (Elements & Compounds) a white crystalline powder derived from bauxite and used in the manufacture of glass and ceramics, aluminium and its salts, and in dyeing. Formula: Al(OH)3 or Al2O3.3H2O Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014