magnesia

A mineral said to be brought from Magnesia.

Magnesium oxid (MgO), a white tasteless substance having a feeble alkaline reaction.

A light earthy white substance, consisting of magnesium oxide (MgO), and obtained by heating magnesium hydrate or carbonate, or by burning magnesium. It has a slightly alkaline reaction, and is used in medicine as a mild antacid laxative. See magnesium.

a bulky white amorphous substance, consisting of a hydrous basic carbonate of magnesium, and used as a mild cathartic.

magnesium oxide

a white solid mineral that occurs naturally as periclase; a source of magnesium