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

Billions of years ago, when Earth was a giant ball of magma, dense droplets of liquid iron rained down into the planet’s depths, and this iron rain took the highly siderophile elements along for the ride, sequestering them in the core. —Quanta Magazine, 4 Aug. 2025

This type of Martian rock was formed by the slow cooling of magma on Mars. —Laura Baisas, Popular Science, 16 July 2025

The plume of magma coming from that hot spot in the ocean floor remains stationary as the Pacific Plate slowly – 2 to 4 inches a year – moves over top of it. —Elizabeth Weise, USA Today, 14 July 2025

From the Nature Communications study, the research team determined that the unrest is likely due to fluid buildup, rather than magma. —Monica Cull, Discover Magazine, 29 May 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