magnesium
Americannoun
noun
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A lightweight, moderately hard, silvery-white metallic element of the alkaline-earth group that burns with an intense white flame. It is an essential component of chlorophyll and is used in lightweight alloys, flash photography, and fireworks. Atomic number 12; atomic weight 24.305; melting point 649°C; boiling point 1,090°C; specific gravity 1.74 (at 20°C); valence 2.
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See Periodic Table
Other Word Forms
Noun Inflected Forms
Etymology
Origin of magnesium
From New Latin, dating back to 1800–10; see origin at magnesia, -ium
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Explanation
Magnesium is a shiny metallic chemical element, and it's also a mineral that humans and other organisms need to be healthy. In nature, magnesium is only found combined with other elements, never on its own. When scientists isolate magnesium from these compounds, it looks silvery-white. Magnesium is an excellent conductor of electricity, and it burns brightly. It's used to make fireworks and flares, and it's often combined with aluminum and zinc to make lightweight metal alloys. Ionized magnesium is necessary for our bodies to function properly: It is involved in over 300 biochemical reactions in the human body. Many people take supplements containing magnesium compounds.
Vocabulary lists containing magnesium
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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Higher sodium can raise blood pressure, while too much magnesium can cause cramping and diarrhea.
From MarketWatch ● Jul. 11, 2026
Taking a cocktail of iron, calcium and magnesium together can reduce absorption rates.
From BBC ● Jun. 20, 2026
Calcium and magnesium matter for bone, muscle and nerve function, but where possible they should come from food.
From Science Daily ● Jun. 6, 2026
Investigations showed the solution was missing magnesium, which caused embryos to stop developing, degrade, or die.
From Barron's ● Jun. 5, 2026
Some hours, eighty or ninety of these flares would go off, one after another, and the night would turn stark and strange in that magnesium glow.
From "All the Light We Cannot See" by Anthony Doerr
Not only are the "bound" magnesiums more bioavailable, but in being so they do not tend to be dumped into the intestines quickly for that well known laxative effect.
From New York Times ● Jan. 5, 2018
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
