A light, silvery metal extracted from bauxite, and a chemical element (symbol Al) with an atomic number of 13. / (countable) A single atom of this element.

plural of aluminium

(Australia, Britain, New Zealand) A very thin, pliable, easily torn sheet of aluminium used for cooking, packaging, cosmetics, and insulation.

(inorganic chemistry) The hydrated form of alumina, having the formula Al(OH)₃; it reacts with bases to form aluminates.

(inorganic chemistry) AlH, formed when aluminium is heated at 1500°C in an atmosphere of hydrogen.

(inorganic chemistry) AlCl, only exists in the gas phase when AlCl₃ is heated with aluminium.

(geology) Aluminium metal, rarely found in nature in oxygen deficient environments such as volcanic mud.

(chemistry, archaic) gallium

(physics) The only stable isotope of aluminium, ²⁷₁₃Al, having thirteen protons and fourteen neutrons

(inorganic chemistry) The solid, Al₂O₃, commonly known as alumina; it occurs as bauxite, sapphire, ruby and other forms; it is used in the manufacture of ceramics