Pluton

Geology: Igneous intrusive body that forms when magma is injected into host rocks and solidifies. Plutons occur in the crust of asteroids undergoing differentiation or planets. Named after Pluto, the Roman god of the underworld. Plutonic rocks are the rocks found within a pluton.

Astronomy: Category of planet including all planets with orbital periods >200 years (Pluto, Charon, and Kuiper Belt objects). In contrast to the classical planets, plutons typically have highly inclined orbits with large eccentricities.

Some or all content above used with permission from J. H. Wittke.