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 advice says drinking water high in minerals is better for constipation than tap water, and magnesium oxide supplements are good for improving symptoms.

From BBC • Oct. 13, 2025

The magnesium formed a thin layer of magnesium oxide on the tantalum surface that appears to keep oxygen from getting through.

From Science Daily • Feb. 5, 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

Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium?

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.