(Science: chemistry) a light earthy white substance, consisting of magnesium oxide, 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. Magnesia alba L.
(Science: medicine) a bulky white amorphous substance, consisting of a hydrous basic carbonate of magnesium, and used as a mild cathartic.
Origin: L. Magnesia, fem. Of Magnesius of the country magnesia, gr. A magnet. Cf. Magnet.