Magnesium n. : 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.

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Taxonomy
magnesium, metal, magnesium alloys, aluminium, Magnesium compounds, magnesium ion, mass, magnesium ions, fire, magnesium oxide, magnesium deficiency, oxide, abundant element, sea water, magnesium metal, high-temperature, additive, burns.

Defination from the web:
... Magnesium (pronounced /mæɡˈniːziəm/, mag-NEE-zee-əm) is a chemical element with the symbol Mg, atomic number 12 and common oxidation number +2. ...