magma

noun

mag·​ma ˈmag-mə How to pronounce magma (audio)
1
archaic : dregs, sediment
2
: a thin pasty suspension (as of a precipitate in water)
3
: molten rock material within the earth from which igneous rock results by cooling
magmatic
mag-ˈma-tik How to pronounce magma (audio)
adjective

Examples of magma in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Earth’s ocean of magma was full of oxygen. — Quanta Magazine, 12 June 2026 In most cases, they're caused by Gloeocapsa magma. — Colleen Sullivan, Martha Stewart, 14 June 2026 The tower was created by cooling magma, rather than industrious aliens, but its mystique is no less majestic for that. — Maureen O'Hare, CNN Money, 16 May 2026 That water is heated by magma below and shoots back upward, bringing with it precious minerals such as copper, zinc and gold, along with the iron and sulfur found in the snail’s shell. — Adam Kovac, Scientific American, 15 May 2026 See All Example Sentences for magma

Word History

Etymology

Middle English, from Latin magmat-, magma, from Greek, thick unguent, from massein to knead — more at mingle

First Known Use

15th century, in the meaning defined at sense 1

Time Traveler
The first known use of magma was in the 15th century

Browse Nearby Words

maglev
magma
magma chamber
See all Nearby Words

Cite this Entry

“Magma.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/magma. Accessed 7 Jul. 2026.

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Kids Definition

magma

noun
mag·​ma ˈmag-mə How to pronounce magma (audio)
: molten rock material within the earth
magmatic
mag-ˈmat-ik How to pronounce magma (audio)
adjective

Medical Definition

magma

noun
mag·​ma ˈmag-mə How to pronounce magma (audio)
1
: a crude mixture of mineral or organic matter in the state of a thin paste
2
: a suspension of a large amount of precipitated material (as in milk of magnesia) in a small volume of a watery vehicle

More from Merriam-Webster on magma

Nglish: Translation of magma for Spanish Speakers

Britannica.com: Encyclopedia article about magma

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