— plutonist , n.
/plooht"n iz'euhm/ , n. Geol.
1. the intrusion of magma and associated deep-seated processes within the earth's crust.
2. ( often cap. ) the disproven theory that all rocks formed by solidification of a molten mass, promulgated by Scottish geologist James Hutton (1726-97).
[ 1840-50; PLUTON(IC) + -ISM ]