from
The Collaborative International Dictionary of English v.0.48
Plutonic \Plu*ton"ic\, a. [Cf. F. plutonique. See {Pluto}.]
1. Of or pertaining to Pluto; Plutonian; hence, pertaining to
the interior of the earth; subterranean.
[1913 Webster]
2. Of, pertaining to, or designating, the system of the
Plutonists; igneous; as, the Plutonic theory.
[1913 Webster]
{Plutonic action} (Geol.), the influence of volcanic heat and
other subterranean forces under pressure.
{Plutonic rocks} (Geol.), granite, porphyry, and some other
igneous rocks, supposed to have consolidated from a melted
state at a great depth from the surface. Cf. {Intrusive
rocks}, under {Intrusive}.
{Plutonic theory}. (Geol.) See {Plutonism}.
[1913 Webster]