from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Magnesium oxide.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. magnesium oxide

from the GNU version of the Collaborative International Dictionary of English

  • n. 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.

from The Century Dictionary and Cyclopedia

  • n. A mineral said to be brought from Magnesia.
  • n. Magnesium oxid (MgO), a white tasteless substance having a feeble alkaline reaction.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

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


Middle English, mineral ingredient of the philosophers' stone, from Medieval Latin magnēsia, from Greek magnēsiā, a kind of ore, from Magnēsiā, Magnesia, an ancient city of Asia Minor.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Middle English magnesia, from late Latin magnesia, from Ancient Greek μαγνησία, after Μαγνησία, a city name in Thessaly, Lydia, and Asia Minor. (Wiktionary)



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