Main Entry:

Plu·to

Pronunciation:

\ˈplü-(ˌ)tō\

Function:

noun

Etymology:

Latin Pluton-, Pluto, from Greek Ploutōn

Date:

14th century

1: the Greek god of the underworld — compare dis2 [New Latin] : a dwarf planet occupying an orbit that crosses the orbit of Neptune

usage 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.