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

Its 12-inch-thick, commercial-grade walls are made of multiple layers of fire-resistant materials like magnesium oxide, sulfate boards and gypsum panels. —Sandra Barrera, Daily News, 14 Mar. 2026

The review found participants who took 320 to 729 milligrams of magnesium citrate or magnesium oxide for three to eight weeks fell asleep around 17 minutes faster and slept about 16 minutes longer than the placebo group. —Kristen Rogers, CNN Money, 13 Mar. 2026

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

Word History

First Known Use

1866, in the meaning defined above

Rhymes for magnesium oxide

• acetaldehyde
• acetanilide
• arabinoside
• cycloheximide
• cyclophosphamide
• diethylamide
• dinucleotide
• ferricyanide
• ferrocyanide
• glutaraldehyde
• glyceraldehyde
• hydroperoxide

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