Meaning

adjective of igneous rock that has solidified beneath the earth's surface; granite or diorite or gabbro

originFrom 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…

Etymology from Wiktionary, CC BY-SA 3.0