The chemical element (symbol Mg) with an atomic number of 12. It is a light, easily flammable, silvery-white alkaline earth metal.

The magnesium salt of sulfuric acid (chemical formula MgSO₄), commonly called Epsom salts.

Any solid solution of magnesium with aluminium, zinc, manganese, silicon, zirconium etc that has a low specific gravity and is used in aircraft manufacture, etc.

a magnesium lamp / the intense light from such a lamp

A thin ribbon of magnesium metal used in laboratory demonstrations and in the magnesium lamp.

A lamp, containing a coil of magnesium ribbon fed into a burner by clockwork, that produced an intense light.

Alternative spelling of magnesium sulfate

A thin magnesium ribbon. / Wire made from an alloy of magnesium and other metals.

(inorganic chemistry) A white powder (MgO) with a high melting point; it occurs naturally as periclase, an ore of magnesium.

(physics) A minor stable isotope of magnesium, ²⁶₁₂Mg, having twelve protons and fourteen neutrons; it amounts to about 11% of the element in nature