[ mag-nee-zhuh, -shuh ]
/ mægˈni ʒə, -ʃə /


a white, tasteless substance, magnesium oxide, MgO, used in medicine as an antacid and laxative.

Origin of magnesia

1350–1400; Middle English: philosophers' stone < Medieval Latin magnēsia < Greek () Magnēsía (líthos) (the stone) of Magnesia; sense development obscure

Related forms

mag·ne·sian, adjective

Definition for magnesia (2 of 2)


[ mag-nee-shee-uh, -zhee-uh ]
/ mægˈni ʃi ə, -ʒi ə /


ancient name of Manisa. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for magnesia

British Dictionary definitions for magnesia


/ (mæɡˈniːʃə) /


another name for magnesium oxide

Derived Forms

magnesian, magnesic (mæɡˈniːsɪk) or magnesial, adjective

Word Origin for magnesia

C14: via Medieval Latin from Greek Magnēsia, of Magnēs ancient mineral-rich region
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for magnesia


[ măg-nēzhə ]


Magnesium oxide.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for magnesia


[ măg-nēzhə ]

A white powder with a very high melting point. It is used to make heat-resistant materials, electrical insulators, cements, fertilizer, and plastics. It is also used in medicine as an antacid and laxative. Chemical formula: MgO.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.