magma

[ mag-muh ]

noun

, plural mag·mas, mag·ma·ta [mag, -m, uh, -t, uh].

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.

magma

/ 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

magma

/ măg′mə /

, or magmas

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.

magma

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.

Notes

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

Derived Forms

• ˈmagmatism, noun
• magmatic, adjective

Other Words From

• mag·mat·ic [mag-, mat, -ik], adjective
• magma·tism noun

Word History and Origins

Origin of magma¹

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

Word History and Origins

Origin of magma¹

C15, from Latin: dregs (of an ointment), from Greek: salve made by kneading, from massein to knead

Example Sentences

Both are clues that the volcanoes are connected by one big caldera, a massive crater that forms when a very large magma chamber in a volcano explodes and empties.

From Science News

This internal melting created magma which, through a plumbing system, was thrust out as lava onto the crust.

From Singularity Hub 

Those elements were some of the last to crystalize out of the magma ocean that covered the young moon and can help reveal details of how that process happened.

From Science News

At her experimental petrology lab at Jacobs-NASA Johnson Space Center, she subjects these samples to extreme pressure and temperature in “mini magma chambers” to recreate the conditions under which they formed.

From Popular-Science

They argue some local source of geothermal heat is needed, such as a magma chamber beneath the surface, to maintain a lake.

From Science News

Underneath our feet tectonic plates shift, magma bubbles, water boils, and both regularly erupt.

From The Daily Beast

When the volcano blew its top, thousands perished, immolated by fire, boiling magma, and ash.

From The Daily Beast

Iron-heavy minerals are believed to have sunk through the magma before floating to the surface in a new form of mountain.

From The Daily Beast

Like magma seeping up through geological faults, this emotion can explode in unexpected ways.

From The Daily Beast

The magma drove upward, melting its way through the fractured rock of the channels under the western side of the island.

From Project Gutenberg

Scientists had arrived, too, and they were taking over much of the detail of keeping track of the magma.

From Project Gutenberg

When the shockwaves get down far enough to crack things open, the gas'll come up, and then steam and ash, and then the magma.

From Project Gutenberg

An average sugar centrifugal will separate 600 pounds of magma perfectly in three minutes.

From Project Gutenberg

Next morning the drained magma is put into a strong bag, and squeezed in a press.

From Project Gutenberg

Related Words

• basalt
• slag

Magma Vs. Lava

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.

Quiz yourself on magma vs. lava!

Should magma or lava be used in the following sentence?

The eruption resulted in a steady flow of _____ from the volcano.