A celestial body that orbits the Sun, has a roughly spherical shape, is farther away from the Sun than Neptune, and shares its orbit with other objects.
Pluto is finally getting its day in the sun, after being stripped of planetary status by astronomers two years ago.
From now on all similar distant bodies in the solar system will be called "plutoids." That's the decision by the International Astronomical Union, which met last week in Oslo, Norway, and announced the decision Wednesday.
—Seth Borenstein, "Pluto's namesakes: Similar bodies are 'plutoids'," The Associated Press, June 11, 2008
The IAU has decided than any object that's orbiting the sun beyond the orbit of Neptune, and large enough for its own gravity to pull it into a spherical shape, will henceforth be classified as a plutoid. And while there are just two such objects so far — Pluto and Eris — scientists are confident they will find more. Telescopic searches and the voyage of NASA's New Horizons spacecraft will be looking. New Horizons, built and managed at the Johns Hopkins University's Applied Physics Lab near Laurel, is due to fly by Pluto in 2015. From there it will cruise out into the icy regions beyond, where more plutoids are likely lurking. The solar system's only other known dwarf planet is the asteroid Ceres. It's big and spherical, too, but because it orbits the sun in the asteroid belt between the orbits of Jupiter and Mars, it's not a plutoid.
—Frank Roylands, "Pluto is now a 'plutoid'," Science Matters, June 11, 2008
On the other hand, Pluto has suffered enough indignities; being demoted to a planet, second class, or plutoid.
—Lawrence Lackey, "Parallels in space," The News & Observer, August 19, 2006
The word plutoid has been around in a couple of different forms over the years. In the 1990s, a band named Rex Pluto used to call its fans Plutoids. Then there's the following nonce coinage:
And now, as the year of Peskabids (People Everyone Should Know About But I Don't) slithers into the pit of oblivion, here's a brand new theme for exhilarating '99: Plutoids, or People Largely Unknown To Otherwise Informed Deipnosophists. (A sadly neglected word, this, meaning persons who converse learnedly over dinner.) The first Plutoid, who will possibly not be surpassed, is a son of the Marquis's country: the conductor Adolphe, or Louis Antoine, Jullien - or to spell his name out in full, Louis George Maurice Adolphe Roch Albert Abel Antonio Alexandre Noe Jean Lucien Daniel Eugene Joseph-le-Brun Joseph Bareme Thomas Thomas Thomas-Thomas Pierre-Cerbon Pierre-Maurel Barthelemi Artus Alphonse Bertrand Dieudonne Emanuel Josue Vincent Luc Michel Jules-de-la-plane Jules-Bazin Julio Cesar Jullien (1812-1860).
—"Smallweed," The Guardian, January 2, 1999