Tag Archives: Pluto


An exercise in astrolexicography

Plutoids and plutinos . . .

When the former planet Pluto was demoted to the status of “dwarf planet” fairly recently, two new words were defined by the International Astronomical Union: plutoid and plutino. If you ask me, these would be damn good words whatever they meant: they belong to that group of words which seem to exist as much because they’re fun to say as because they’re needed.

Several weeks ago one of my contacts on Twitter, @Exoplanetology, came up with the word exoplutoid, meaning a plutoid in a planetary system other than our own.

Should you wish to know, a plutino is an object which, like Pluto, orbits the Sun twice for every three orbits made by Neptune. (This is called a 2:3 resonance, and the object remains trapped in that orbit.) A plutoid, roughly speaking, is simply a dwarf planet which orbits the Sun further out than Neptune does.

I suppose an exoplutoid might be a dwarf planet in another star system, further from its star than the last convincing planet.

Nice words. Are there more?

Plutonyms in the dictionary

Let’s proceed with caution. A look at the dictionary reveals that a number of pluto- words already exist. Furthermore, not all of them are anything to do with Pluto. Plutocrats, being plutocratic in a plutocracy, get their name from the Greek word ploutos, which means wealth.

In geology, plutonic relates to rocks which have solidified from a molten state at the fiery depths associated with the god Pluto and his underworld, and a pluton is a “body of instrusive igneous rock”. Geology also uses the word plutonism in this connection.

In chemistry, the element plutonium has nothing to do with plutonism; the elements uranium, neptunium and plutonium take their names (rather nicely) from Uranus, and Neptune and Pluto, which were all planets at the time.

Plutogenous neologisms

Given the existence of all these words already, are we to conclude that Pluto has contributed all it can to the English language? I think not!

There are still plenty of Pluto-related situation requiring words. Some of the situations are more “serious” than others. But all need words, and it is my pleasure to present them to you. They are grouped by function rather than alphabetically. Use and enjoy.

similar in material or structure to Pluto.
exoplutoid, exoplutino:
a body in another planetary system analogous to a plutoid or plutino in ours.
originating from, or generated or caused by, Pluto and its status. For example, plutogenous fisticuffs might result from a heated discussion about its classification. See plutonym, below.
removal of Pluto or a Pluto-like object, e.g. from a list of recognised planets or (as a more advanced engineering project) from a planetery system
relating to the creation of Pluto-like objects, i.e. to plutogenesis.

a word created with reference to Pluto and its status; that is, one which enters the language as a plutogenous neologism.
the study of plutonyms.
the creation of a dictionary or glossary of plutonyms
an inability to remember what Pluto is officially classified as these days.
suffering from or relating to plutamnesia.
someone who suffers from plutamnesia.
1. condition of accidentally using the wrong plutonym, e.g. calling a plutoid a plutino or describing plutogenous situation as plutogenic. The corresponding adjective is paraplutotic.
2. erroneous identification of an object as Pluto.

Got any more? Post them here and I’ll do the plutolexicographer’s job of gathering them together, time and energy permitting. Especially if they’re good.