magma

noun

mag·​ma ˈmag-mə 

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 

adjective

Examples of magma in a Sentence

Recent Examples on the Web

Researchers at Italy's National Institute of Geophysics and Volcanology are monitoring signals of magma movement within the Earth's crust to detect when the next eruption at Etna is imminent, according to a paper published in Science earlier this month. —Julia Jacobo, ABC News, 22 Oct. 2025

The deep crater of the volcano now filled with water sits atop the still-active magma column of molten rock. —Literary Hub, 22 Oct. 2025

Volcanic activity can also trigger earthquakes, especially when magma shifts beneath the surface or alters pressure in surrounding rock. —Shane Croucher, MSNBC Newsweek, 10 Oct. 2025

The searing layer of magma beneath the planet’s crust continuously releases heat through the decay of radioactive elements such as uranium (U) and potassium (K). —Georgina Jedikovska, Interesting Engineering, 10 Oct. 2025

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

Kids Definition

magma

noun

mag·​ma ˈmag-mə 

: molten rock material within the earth

magmatic

mag-ˈmat-ik 

adjective

Medical Definition

magma

noun

mag·​ma ˈmag-mə 

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