Plutonic

From Ancient Greek Πλούτων (Ploútōn, “Pluto, Greek and Roman god of the underworld”) (from πλοῦτος (ploûtos, “riches, wealth”) (ultimately from Proto-Indo-European *plew- (“to fly; to flow; to run”)) + -ων (-ōn)) +‎ -ic (suffix forming adjectives meaning ‘of or pertaining to’). The English word is cognate with Middle French plutonique (modern French plutonique (“of or pertaining to Pluto, the underworld, or the interior of the Earth”)).[1]

• (Received Pronunciation) IPA^(key): /pluːˈtɒnɪk/
• (General American) IPA^(key): /pluˈtɑnɪk/
• Hyphenation: plu‧ton‧ic

Plutonic (comparative more Plutonic, superlative most Plutonic)

1. (Greek mythology, Roman mythology) Synonym of Plutonian (“of or relating to Pluto, the Greek and Roman god of the underworld; demonic, infernal”)
2. (by extension) Synonym of Plutonian (“of, relating to, or having characteristics associated with the underworld; dark, gloomy; mournful”)
   • 1911, G. K. Chesterton, “The Sins of Prince Saradine”, in The Innocence of Father Brown:

     a dark, handsome lady, of no little majesty, and rather like a plutonic Madonna

3. (by extension, geology, mineralogy) Of or pertaining to rocks formed deep in the Earth's crust, rather than by volcanoes at the surface of the Earth.

   Synonyms: abyssal, intrusive, Plutonian

   • 1912, Arthur Conan Doyle, The Lost World […], London, New York, N.Y.: Hodder and Stoughton, →OCLC:

     These cliffs, I may remark, are basaltic, and therefore plutonic.

4. (by extension, geology, historical) Of, pertaining to, or supporting plutonism (“the theory that the rocks of the Earth were formed in fire by volcanic activity, with a continuing gradual process of weathering and erosion, then deposited on the sea bed, re-formed into layers of sedimentary rock by heat and pressure, and raised again”).

   Synonym: Plutonian

• plutonic