magnesium oxide

noun

: a white highly infusible compound MgO used especially in refractories, cements, insulation, and fertilizers, in rubber manufacture, and in medicine as an antacid and mild laxative

Examples of magnesium oxide in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
At the Autonomous University of Madrid, the researchers conducted experiments to fabricate a Josephson junction with a superconducting vanadium electrode on one side and an iron electrode on the other, with magnesium oxide as the barrier. Ameya Paleja, Interesting Engineering, 30 Dec. 2025 Forms like magnesium citrate and glycinate are absorbed better than forms like magnesium oxide. Sohaib Imtiaz, Verywell Health, 22 Dec. 2025 Similarly, magnesium is available in different forms, including magnesium citrate, magnesium oxide, and magnesium chloride. Ruth Jessen Hickman, Health, 11 Dec. 2025 For example, recommendations have been made for magnesium oxide supplements, kiwifruits and high mineral-content water, highlighting that these may improve cardinal symptoms of constipation. New Atlas, 26 Oct. 2025 See All Example Sentences for magnesium oxide

Word History

First Known Use

1866, in the meaning defined above

Time Traveler
The first known use of magnesium oxide was in 1866

Cite this Entry

“Magnesium oxide.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/magnesium%20oxide. Accessed 10 Jan. 2026.

Kids Definition

magnesium oxide

noun
: a white earthy solid that consists of magnesium and oxygen and is used especially in fertilizers and rubber, as a mild laxative, and against acid in the stomach

Medical Definition

magnesium oxide

noun
: a white highly infusible compound MgO used especially in refractories, cements, insulation, and fertilizers, in rubber manufacture, and in medicine as an antacid and mild laxative

More from Merriam-Webster on magnesium oxide

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