Mag*ne"si*a [L. Magnesia, fem. of Magnesius of the country Magnesia, Gr. a magnet. Cf. Magnet.] Chem.
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.] Med. Chem., a bulky white amorphous substance, consisting of a hydrous basic carbonate of magnesium, and used as a mild cathartic.
© Webster 1913.