Pluto

noun

Plu·​to ˈplü-(ˌ)tō 

1

: the Greek god of the underworld compare dis

2

[New Latin] : a dwarf planet occupying an orbit that crosses the orbit of Neptune

Is Pluto a planet?: Usage Guide

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.

Examples of Pluto in a Sentence

Recent Examples on the Web

The Oort Cloud lies far beyond Pluto and is home to millions of comets. —Jamie Carter, Forbes.com, 28 June 2025

On June 28, Mercury will make a revelatory opposition to Pluto retrograde in Aquarius, signaling a clash that’s bound to shake things up. —Valerie Mesa, People.com, 28 June 2025

The brand new channel will live on Pluto TV, offering exclusive Tastemade content on live fire cooking. —Katie Campione, Deadline, 26 June 2025

Previously, Pluto was thought to have a pretty stable orbit, but the new simulations show that over the course of about five billion years, there’s a 4 percent chance for Pluto to be ejected from the solar system entirely. —Phil Plait, Scientific American, 26 June 2025

Word History

Etymology

Latin Pluton-, Pluto, from Greek Ploutōn

First Known Use

14th century, in the meaning defined at sense 1

Rhymes for Pluto

• basuto
• prosciutto

Kids Definition

Pluto

noun

Plu·​to ˈplüt-ō 

: a large object in the outermost part of the solar system that is often considered one of the planets see note at planet