magnesium oxide

American  

noun

Chemistry.

1. magnesia.

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magnesium oxide British  

noun

1. Also called: magnesia.  a white tasteless substance occurring naturally as periclase: used as an antacid and laxative and in refractory materials, such as crucibles and fire bricks. Formula: MgO

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Etymology

Origin of magnesium oxide

First recorded in 1905–10

Compare meaning

How does magnesium-oxide compare to similar and commonly confused words? Explore the most common comparisons:

• magnesium vs. magnesium oxide
• magnesium oxide vs. magnesium sulfate
• magnesium hydroxide vs. magnesium oxide

Example Sentences

The research also found that supplements such as psyllium fiber, certain probiotics, and magnesium oxide may provide additional relief.

From Science Daily • Oct. 22, 2025

It used magnesium oxide boards, which do not burn, during testing and did not reveal this in marketing literature.

From BBC • Sep. 4, 2024

That reaction would leave magnesium oxide powder, which when spread thin would rapidly react with CO2 from the atmosphere, re-forming magnesite, completing a cycle that could be repeated over and over.

From Science Magazine • Sep. 3, 2020

When magnesium burns in air a white flaky ash of magnesium oxide is produced.

From Textbooks • Feb. 14, 2019

Examine and burn a piece of magnesium ribbon, noting the white compound of magnesium oxide which is formed.

From Physiology and Hygiene for Secondary Schools by Walters, Francis M.