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

The United States Geological Survey said fallout had created hazardous conditions in downwind areas, with one resident reporting more than an inch of tephra — a mix of magma, rock and volcanic glass — on the roads of a golf course subdivision. —Marc Ramirez, USA Today, 10 Mar. 2026

The latest research also provides strong evidence supporting long-standing theories of the Moon’s geological evolution, including the existence of an early global magma ocean that cooled unevenly, leaving distinct crust-mantle and chemical differences between the near and far sides. —Bojan Stojkovski, Interesting Engineering, 7 Mar. 2026

The material, left over from when the moon’s magma ocean solidified, is a combination of potassium, rare Earth elements and phosphorus found in lunar rocks. —Ashley Strickland, CNN Money, 21 Feb. 2026

Ailsa Craig’s rocks formed around 60 million years ago when magma pushed into a relatively shallow layer of the Earth’s crust during the rifting that formed the Atlantic Ocean. —Andrea Thompson, Scientific American, 10 Feb. 2026

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