- a silver-white metallic element, light in weight, ductile, malleable, and not readily corroded or tarnished, occurring combined in nature in igneous rock, shale, clay, and most soil: used in alloys and for lightweight utensils, castings, airplane parts, etc. Abbreviation: alum.; Symbol: Al; atomic weight: 26.98; atomic number: 13; specific gravity: 2.70 at 20°C.
- of, relating to, or containing aluminum: an aluminum frying pan.
