igneous

Etymology

It is borrowed from Latin igneus (“of fire, fiery”), from ignis (“fire”),^{[2][3][4][5][6][7]} with the suffix -ous.^[2][8][9] The Latin noun is from Proto-Indo-European *egni- (“fire”),^[3] which de Vaan reconstructs as *h₁n̥gʷ-ni-.^[10] It is cognate with Lithuanian ugnìs (“fire”) and Latvian uguns (“fire”).^[11][10] Barnhart adds that in some uses the word may have been borrowed from Middle French igné, since English has other adjectives in -eous matching French ones in -é.^[7]

Earliest recorded meaning

Produced by the action of fire: 1661, in Glanvill's Vanity of Dogmatizing.^[2] Barnhart dates the sense "fiery" to 1664 and "produced by fire" to 1665,^[7] and Merriam-Webster gives 1664.^[6]

Semantic evolution

Earlier adjectives in the sense "fiery" were ignean (1630s) and ignic (1610s).^[3] Johnson (1755) glossed it as "containing fire; emitting fire; having the nature of fire".^[12] Its geological sense, "produced by volcanic forces", dates from 1791, at first in contrast with aqueous,^[3][2] and the SOED likewise places it in the late 18th century.^[9] This is now the main use: Dictionary.com lists it first.^[13]

Timeline

• 1661 – produced by the action of fire.^[2]
• 1664 – of or like fire; fiery.^[2][7]
• 1791 – in geology, produced by volcanic forces.^[3]

Meanings

Adjective

1. (geology) Of rock, formed by the solidifying of magma or lava; relating to such rock: Granite is an igneous rock.^[14][4][6]
2. Of, relating to or like fire; fiery.^[14][4][6]
3. Produced by the action of fire.^[2][15]

Word family

• nonigneous

Related words

• ignite
• ignition
• Agni
• gelignite
• ignis fatuus
• ignescent

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
5. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
6. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
7. ^ a b c d Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
9. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
10. ^ a b de Vaan, Michiel (2008), Etymological Dictionary of Latin and the other Italic Languages, Leiden Indo-European Etymological Dictionary Series 7, Leiden; Boston: Brill
11. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
12. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
14. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins
15. ^ Webster's New World College Dictionary (2014), 5th ed., Boston: Houghton Mifflin Harcourt