- In geology, a pluton is any body of igneous rock that solidified below the Earth's surface.
AND PLANETARY SCIENCE
- In planetary astronomy, pluton was a proposed category
of planetary object, of which Pluto would have
been the prototype, consisting of planets that takes at least 200 years
to complete one orbit of the Sun. Astronomers instead adopted the term
"dwarf planet" to distinguish smaller
planetary objects from the eight "classical planets," Mercury through