Magnesia /(?; 277)/

Mag·ne·si·a

Magnesia

n.
  1. 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. (Chem.)

Phrases & Compounds
Magnesia alba
a bulky white amorphous substance, consisting of a hydrous basic carbonate of magnesium, and used as a mild cathartic.