Definition of Pluto in English:

Share this entry


Pronunciation: /ˈplo͞odō/
1 Greek Mythology The god of the underworld. Also called Hades.
2 Astronomy A small planetary body orbiting the sun, discovered in 1930 by Clyde Tombaugh.

Pluto usually orbits beyond Neptune at an average distance of 5,900 million km from the sun, although its orbit is so eccentric that at perihelion it is closer to the sun than Neptune (as in 1979–99). Pluto is smaller than earth’s moon (diameter about 2,250 km), but it has its own large satellite (Charon), and four other small moons. From the time of its discovery it was regarded as the ninth (outermost) planet of the solar system, but in the 1990s its unusual characteristics led astronomers to question its planetary nature. In August 2006, the International Astronomical Union formally declared Pluto to be a dwarf planet rather than a planet proper. Pluto was visited by NASA’s space probe, New Horizons, in 2015.


Via Latin from Ploutōn, the Greek name of the god of the underworld.

Words that rhyme with Pluto

Bhutto, butoh, Maputo, prosciutto, ritenuto, sostenuto, tenuto

For editors and proofreaders

Syllabification: Plu·to

Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.