plutodemote or devalue a person or thing; a pluto (not capitalized) is someone or something that has lost its status (On August 24, 2006, the International Astronomical Union, which decides the official names of all celestial bodies, stated that Pluto was not a true planet because it?s ?too small and doesn?t dominate its neighborhood.? They dubbed Pluto a dwarf planet. This means that there are now only eight planets in the solar system.)Abused, Confused, & Misused Words by Mary Embree Copyright © 2007, 2013 by Mary EmbreePlu·to  (plo?o?t?)n.1. Roman Mythology The god of the dead and the ruler of the underworld, identified with the Greek Hades.2. A dwarf planet having a sidereal period of revolution about the sun of 248.5 years, a highly elliptical orbit with a perihelion distance of 4.4 billion kilometers (2.8 billion miles) and an aphelion distance of 7.4 billion kilometers (4.6 billion miles), and a mean equatorial diameter of 2,302 kilometers (1,485 miles), less than half that of Earth. Until 2006, Pluto was classified as the ninth planet in the solar system. See Usage Note at planet.[Latin Pl?t?, Pl?t?n-, from Greek Plout?n, from ploutos, wealth (from the belief that the underworld was the source of wealth from the ground); see pleu- in Indo-European roots.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.Pluto (?plu?t??) n (Classical Myth & Legend) classical myth the god of the underworld; HadesPluto (?plu?t??) n (Celestial Objects) the second-largest dwarf planet in the solar system, located in the Kuiper belt; discovered in 1930 by Clyde Tombaugh (1906?97); classified as a planet until 2006, when it was reclassified as a dwarf planet. It has a diameter of 2390 kmvb (tr) 1. to reduce (something) in status or importance 2. to put an end to (something)[Latin, from Greek Plout?n, literally: the rich one]PLUTO (?plu?t??) n (Historical Terms) the code name of pipelines laid under the English Channel to supply fuel to the Allied forces landing in Normandy in 1944[C20: from p(ipe)l(ine) u(nder) t(he) o(cean)]Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014Plu?to (?plu to?) n. 1. Hades (def. 2). 2. the planet ninth in order from the sun, having an equatorial diameter of about 1400 mi. (2250 km), a mean distance from the sun of 3.674 billion mi. (5.914 billion km), a period of revolution of 248.53 years, and one known moon. Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.Plu·to (plo?o?t?) A dwarf planet that until 2006 was classified as the ninth planet in our solar system. It has a diameter about one-sixth that of Earth. It orbits the sun once every 248 years. Its orbit crosses that of Neptune. It has an average surface temperature of -369°F (-223°C). See Table at solar system. See Note at planet.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.