Mag*ne"si*um (?), n. [NL. & F. See Magnesia.] (Chem.) A light silver-white metallic element, malleable and ductile, quite permanent in dry air but tarnishing in moist air. It burns, forming (the oxide) magnesia, with the production of a blinding light (the so-called magnesium light) which is used in signaling, in pyrotechny, or in photography where a strong actinic illuminant is required. Its compounds occur abundantly, as in dolomite, talc, meerschaum, etc. Symbol Mg. Atomic weight, 24.4. Specific gravity, 1.75.

• A light, flammable, silvery metal, and a chemical element (symbol Mg) with an atomic number of 12.
  

German
• magnesium