Noun | 1. | ![]() metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc. potash alum, potassium alum, alum - a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum alum, ammonia alum, ammonium alum - a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum bauxite - a clay-like mineral; the chief ore of aluminum; composed of aluminum oxides and aluminum hydroxides; used as an abrasive and catalyst Duralumin - an aluminum-based alloy |