Magnesia

from WordNet (r) 3.0 (2006)
magnesia
    n 1: a white solid mineral that occurs naturally as periclase; a
         source of magnesium [syn: {periclase}, {magnesia},
         {magnesium oxide}]
    
from The Collaborative International Dictionary of English v.0.48
Magnesia \Mag*ne"si*a\ (?; 277), n. [L. Magnesia, fem. of
   Magnesius of the country Magnesia, Gr. h` Magnhsi`a li`qos a
   magnet. Cf. {Magnet}.] (Chem.)
   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}.
   [1913 Webster]

   {Magnesia alba} [L.] (Med. Chem.), a bulky white amorphous
      substance, consisting of a hydrous basic carbonate of
      magnesium, and used as a mild cathartic.
      [1913 Webster]
    

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