Dictionary
Thesaurus
Encyclopedia
Translator
Web

Pluto

 - 5 dictionary results

Plu⋅to

[ploo-toh]
–noun
1. Classical Mythology. a name given to Hades, under which he is identified by the Romans with Orcus.
2. Astronomy. the planet ninth in order from the sun, having an equatorial diameter of about 2100 miles (3300 km), a mean distance from the sun of 3.674 billion miles (5.914 billion km), a period of revolution of 248.53 years, and one known moon, Charon.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
Cite This Source Link To Pluto
Plu·to   (plōō'tō)   
n.  
  1. Roman Mythology The god of the dead and the ruler of the underworld.

  2. A dwarf planet that until 2006 was classified as the ninth planet in our solar sytem, having a sidereal period of revolution about the sun of 248.5 years, 4.4 billion kilometers (2.8 billion miles) distant at perihelion and 7.4 billion kilometers (4.6 billion miles) at aphelion, and a diameter less than half that of Earth. See Usage Note at planet.


[Latin Plūtō, Plūtōn-, from Greek Ploutōn, from ploutos, wealth (from the belief that the underworld was the source of wealth from the ground); see pleu- in Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Cultural Dictionary

Pluto

The Roman name of Hades, the Greek and Roman god of the underworld and ruler of the dead.

Note: The planet Pluto is usually the most distant planet in the solar system.

Pluto

In astronomy, the smallest of the major planets, usually ninth from the sun. Pluto was discovered in 1930 and is named for the Roman god of the underworld. (See solar system)

Note: Astronomers in the late nineteenth century, thinking they saw disturbances in the orbits of Uranus and Neptune, suspected that there was a ninth planet, not yet discovered, exerting gravitation on the other two. In the early twentieth century, astronomers searched for that planet and found Pluto. Ironically, Pluto is much too small to be the planet they sought.
Note: Pluto's orbit is a stretched ellipse, unlike the orbits of the other major planets, which are nearly circular. As a result, for a period ending in 1999, Pluto was actually closer to the sun than Neptune.
Note: There is some debate among astronomers as to whether Pluto should really be classified as a planet or should instead be considered a large asteroid-like body.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Word Origin & History

Pluto 
Roman god of the underworld, brother of Zeus and Neptune, from L. Pluto, from Gk. Plouton "god of wealth," lit. "wealth, riches," probably originally "overflowing," from PIE *pleu- "to flow. The planet (since downgraded) was discovered 1930 by C.W. Tombaugh; Minerva also was suggested as a name for it. The cartoon dog first appeared in Walt Disney's "Moose Hunt," released April 1931.
Online Etymology Dictionary, © 2001 Douglas Harper
Cite This Source
Search another word or see Pluto on Thesaurus | Reference
FacebookTwitterFollow us: