magnesium

noun

mag·​ne·​sium mag-ˈnē-zē-əm 

-zhəm

: a silver-white malleable ductile light metallic element that occurs abundantly in nature and is used in metallurgical and chemical processes, in photography, signaling, and pyrotechnics because of the intense white light it produces on burning, and in construction especially in the form of light alloys see Chemical Elements Table

Examples of magnesium in a Sentence

Recent Examples on the Web

The tolerable upper intake level (UL) for magnesium is 350 mg daily, the highest amount that usually won't cause side effects. —Brittany Lubeck, Verywell Health, 27 Jan. 2026

Certain health conditions can affect how well your body absorbs magnesium and may influence how quickly magnesium works for sleep. —Emmanuella Ogbonna, Health, 26 Jan. 2026

Speaking of the formula, it’s enhanced with a variety of electrolytes, including sodium, potassium, magnesium, zinc, and copper—think of it like your favorite sports drink, but for your face. —Alicia Geigel, Southern Living, 23 Jan. 2026

Almond butter has more than five times the calcium as peanut butter, and more iron, magnesium, phosphorus, potassium, and vitamin E, says Guevara. —Kirsten Nunez, Martha Stewart, 17 Jan. 2026

Word History

Etymology

New Latin, from magnesia

First Known Use

1812, in the meaning defined above

Phrases Containing magnesium

• magnesium carbonate
• magnesium chloride
• magnesium hydroxide
• magnesium oxide
• magnesium sulfate

Rhymes for magnesium

• caesium
• cesium
• trapezium

Kids Definition

magnesium

noun

mag·​ne·​sium mag-ˈnē-zē-əm 

-zhəm

: a silver-white metallic element that is light and easily worked, burns with a dazzling light, and is used in making lightweight alloys see element

Medical Definition

magnesium

noun

mag·​ne·​sium mag-ˈnē-zē-əm  -zhəm 

: a silver-white light malleable ductile metallic element that occurs abundantly in nature (as in bones and seeds and in the form of chlorophyll in the green parts of plants) and is used in metallurgical and chemical processes, in photography, in signaling, and in the manufacture of pyrotechnics because of the intense white light it produces on burning, and in construction especially in the form of light alloys

—symbol Mg see Chemical Elements Table