Definition of Pluto
1 : the Greek god of the underworld — compare dis
2 [New Latin] : a dwarf planet occupying an orbit that crosses the orbit of Neptune
Usage Discussion of pluto
In 2006 the International Astronomical Union defined planet in such a way as to exclude Pluto, reclassifying it instead as a dwarf planet. Although discussion of the matter continues, the change has been widely accepted.
Origin and Etymology of pluto
Latin Pluton-, Pluto, from Greek Ploutōn
First Known Use: 14th century
PLUTO Defined for English Language Learners
Definition of Pluto for English Language Learners
: the object in our solar system that in the past was thought to be the planet farthest from the sun but that is no longer considered to be a planet
Seen and Heard
What made you want to look up Pluto? Please tell us where you read or heard it (including the quote, if possible).