magma

 
Pronunciation: /ˈmagmə/

noun (plural magmas or magmata /-mətə/)

[mass noun]
  • hot fluid or semi-fluid material below or within the earth’s crust from which lava and other igneous rock is formed on cooling: when red-hot magma comes into contact with seawater, an explosion results [count noun]: basaltic magmas are normally expelled at the surface in a very hot and fluid state

Derivatives

magmatic

Pronunciation: /-ˈmatɪk/
adjective

Origin:

late Middle English (in the sense 'residue of dregs after evaporation or pressing of a semi-liquid substance'): via Latin from Greek magma (from massein 'knead')