rhizoverbBeta
DictionarymagmaMolten underground rock
noun

magma

MAG-muh/ˈmæɡmə/

Molten rock beneath Earth's surface.

The cutaway shows magma beneath Earth’s surface.

A geological cutaway of volcanic rock showing glowing molten magma pooled beneath the earth surface, no surface lava, no arrows or labels.
Etymology
magmaGreekthick ointment

Greek magma meant a thick ointment. In English, the word initially referred to dregs or a crude mixture before acquiring its geological meaning of molten or semi-molten rock.

In context

HISTORY22:32
Scientists think this reversal explains the stripes either side of the ocean ridge. In the 1960s, geologists discovered that molten volcanic rock, known as magma, swelled up from deep underground to create the ridges in the Atlantic and Pacific.
Inside the Marianas Trench: Earth's Deepest Point | How the Earth Was Made (S1, E2) | Full Episode

More examples

  • The rock formed as magma cooled underground.
  • Scientists studied movement in the magma chamber.
  • Pressure rose as fresh magma entered the reservoir.

Forms

magma

Similar words

lava
Lava has reached the surface; magma remains beneath it.
melt
Melt is any molten material; magma is a geological mixture beneath Earth’s surface.