Magma
Molten or partly molten silicate or other geological material at depth, often containing crystals, dissolved gases and melt; solidification can produce igneous rock.
Language and route: English via Latin magma. Ancient Greek μάγμα (mágma), a kneaded or thick substance, entered Latin for a thick residue and subsequently English before its specialised geological use.
Literal gloss: kneaded mass; paste
The name and its history
No individual geological coiner securely identified · Geological English attested by 1859
- What does the word literally mean?
- ‘Kneaded paste’ or ‘thick mass’, not literally ‘molten stone’.
- What did the original author mean?
- The English word long denoted a thick mixture or residue. Nineteenth-century geology specialised it for molten or partially molten rock within the Earth.
- Why was the name needed?
- A precise noun was needed for a potentially mobile rock-forming material before it erupted or crystallised; conflating subsurface magma with observed lava obscured the process.
- What evidence supported the original concept?
- Volcanic eruptions, intrusive relations, contact metamorphism and changing experimental understanding of silicate melting; no single modern chemical definition governed the nineteenth-century lexical shift.
- How has geology changed the concept?
- A magma is typically a multiphase system, not necessarily a homogeneous liquid; lava is magma erupted at the surface, so the two are related but not identical terms.
Further historical context
Greek medical/craft vocabulary travelled through Latin and ordinary English long before geological adaptation.
Etymological evidence dates geological English usage by 1859; that does not establish which geologist coined the technical sense.
Editorial qualification
Do not imply the Greek origin described molten rock, nor claim an exact nineteenth-century first publication.
Related names
Igneous · Pegmatite · Granite · Metamorphic
Sources
- Online Etymology Dictionary, magma — Greek → Latin → English; shift from paste/dregs to molten rock
- Online Etymology Dictionary, igneous — English chronology, Latin origin; geological use attested by 1791
- Le Maitre et al. (2002), Igneous Rocks: A Classification and Glossary of Terms (IUGS) — International igneous nomenclature and modal proportion conventions