magma

American  

[mag-muh] / ˈmæg mə /

noun

• magmas,
  plural
• magmata
  plural

1. Geology. molten material beneath or within the earth's crust, from which igneous rock is formed.

2. any crude mixture of finely divided mineral or organic matter.

3. Chemistry, Pharmacology. a paste composed of solid and liquid matter.

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magma British  

/ ˈmæɡmə, mæɡˈmætɪk /

noun

1. a paste or suspension consisting of a finely divided solid dispersed in a liquid

2. hot molten rock, usually formed in the earth's upper mantle, some of which finds its way into the crust and onto the earth's surface, where it solidifies to form igneous rock

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magma Scientific  

/ măg′mə /

1. The molten rock material that originates under the Earth's crust and forms igneous rock when it has cooled. When magma cools and solidifies beneath the Earth's surface, it forms what are known as intrusive rocks. When it reaches the Earth's surface, it flows out as lava and forms extrusive (or volcanic) rocks.

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magma Cultural  

1. Molten rock usually located deep within the mantle of the Earth that occasionally comes to the surface through cracks in the mantle or through the eruption of volcano es.

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Usage

What’s the difference between magma and lava? Magma is what molten (melted) rock is called when it’s under the earth’s surface. Lava is what molten rock is called when it flows out of a volcano or volcanic vent. To be clear, in popular use, magma and lava are essentially different names for the same liquid-hot, charred orange ooze—which name is used depends on whether it is above or below the surface. However, geologists and volcanologists have their reasons for using the two different terms to distinguish between forms of what is the same substance. Magma doesn’t always become lava—sometimes it cools and solidifies beneath the earth's surface. Sometimes, it collects in what’s known as a magma chamber. When it does reach the surface, it flows out as lava. The rock that’s formed when it hardens and cools can also be called lava, though this use of the term is uncommon outside of technical, scientific contexts. The word lava is perhaps the more well-known of the two because that’s the one we see when volcanoes erupt (or when the floor turns into it). Here is an example of magma and lava used correctly in the same sentence. Example: Lava began flowing from the volcano three days after scientists detected movement of magma underground. Want to learn more? Read the full breakdown of the difference between magma and lava.

Discover More

When magma cools and solidifies, it forms igneous rock, of which lava is one type.

Other Word Forms

Derived Forms

• magmatism
  noun
• magmatic
  adjective

Inflected Forms

Nouns

• magmas
  plural
• magmata
  plural

Etymology

Origin of magma

1400–50; late Middle English < Latin: dregs, leavings < Greek mágma kneaded mass, salve, equivalent to mag- (base of mássein to knead, press; see mass) + -ma noun suffix of result

Explanation

That red hot liquid rock that spews violently out of erupting volcanoes? That's lava. But before the lava rises to the earth's surface it's called magma. Although lava and magma are often used interchangeably, technically magma is the name for the hot molten rock (mixed with gases and mineral crystals) that collects in chambers beneath the Earth's crust. Once the magma breaks through the Earth's surface and flows down the volcano, you can call it lava. There are about 1500 active volcanoes on the Earth and at least 80 under the oceans — which add up to a lot of magma and possible lava.

Example Sentences

See Examples For:

magma magmas

By identifying areas where the waves moved at lower velocities, the researchers were able to pinpoint the likely location of magma.

From Science Daily ● Aug. 5, 2026

Scientists have discovered an enormous body of magma deep beneath Tuscany, even though the region shows few of the surface clues typically associated with such systems.

From Science Daily ● Aug. 5, 2026

Over geological timescales, a magma body of this size could theoretically play a role in the development of a supervolcano.

From Science Daily ● Aug. 5, 2026

These simulations were designed to show how magma moves and changes as it travels upward through Earth's crust.

From Science Daily ● Aug. 1, 2026

Worst of all was his head: a helmet of twisted rock and metal with no particular shape—just jagged spikes and pulsing patches of magma.

From "The House of Hades" by Rick Riordan

The chemical composition of the crystals, plucked from rocks in Australia, hint that they formed from magmas doped with freshwater, a team of scientists argues.

From Science Magazine ● Apr. 30, 2024

He thinks that under the right conditions, similar light isotope ratios could have arisen in magmas interacting with seawater.

From Science Magazine ● Apr. 30, 2024

Understanding what went into making TTGs and the magmas they formed from has been difficult, because so many geological processes occurred between their initial melting and ultimate crystallization.

From Science Daily ● Jan. 31, 2024

The study, published today in Nature Geoscience, reveals a key step in the genesis of these distinctive magmas.

From Science Daily ● Jan. 15, 2024

When magmas reach the surface red hot, they form extrusive rocks, such as volcanic rocks.

From Let's Collect Rocks and Shells by Shell Union Oil Corporation

Related Words

• basalt
• slag