from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun In the traditional model of solar systems, a celestial body larger than an asteroid or comet, illuminated by light from a star, such as the sun, around which it revolves.
  • noun A celestial body that orbits the sun, has sufficient mass to assume nearly a round shape, clears out dust and debris from the neighborhood around its orbit, and is not a satellite of another planet.
  • noun One of the seven celestial bodies, Mercury, Venus, the moon, the sun, Mars, Jupiter, and Saturn, visible to the naked eye and thought by ancient astronomers to revolve in the heavens about a fixed Earth and among fixed stars.
  • noun The collection of life forms supported on Earth.
  • noun People as a whole; humankind or the general public.
  • noun One of the seven revolving astrological celestial bodies that in conjunction with the stars are believed to influence human affairs and personalities.

from The Century Dictionary.

  • noun A star other than a fixed star: a star revolving in an orbit.
  • noun Same as planeta

from the GNU version of the Collaborative International Dictionary of English.

  • noun (Astron.) A celestial body which revolves about the sun in an orbit of a moderate degree of eccentricity. It is distinguished from a comet by the absence of a coma, and by having a less eccentric orbit. See solar system.
  • noun A star, as influencing the fate of a men.
  • noun (Mach.) See Epicyclic train, under Epicyclic.
  • noun a gear wheel which revolves around the wheel with which it meshes, in an epicyclic train.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A large body which directly orbits any star (or star cluster) but which has not attained nuclear fusion.
  • noun In phrases such as the planet, this planet, sometimes refers to the Earth.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun a person who follows or serves another
  • noun any celestial body (other than comets or satellites) that revolves around a star
  • noun (astronomy) any of the nine large celestial bodies in the solar system that revolve around the sun and shine by reflected light; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto in order of their proximity to the sun; viewed from the constellation Hercules, all the planets rotate around the sun in a counterclockwise direction


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English, from Old French planete, from Late Latin planēta, from Greek planētēs, variant of planēs, planēt-, from planāsthai, to wander; see pelə- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English planete, from Old English planēta ("planet, chasuble"), from Latin planeta, planetes, from Ancient Greek πλανήτης (planētēs) variant of πλάνης (planēs, "wanderer, planet"), from Ancient Greek πλανάω (planáō, "wander about, stray"), of unknown origin. Perhaps from a Proto-Indo-European *pel- (“to wander, roam”), cognate with Latin pālor ("wander about, stray"), Old Norse flana ("to rush about"), Norwegian flanta ("to wander about"). More at flaunt.


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  • “Wanderer�?

    October 14, 2007

  • This makes a lot of sense. Besides the sun and the moon, the planets are the only heavenly bodies which don't follow progress through the ecliptic.

    October 14, 2007

  • And comets, right?

    October 15, 2007

  • Of course. comet actually comes from the Greek for long-haired star, so they were considered more like stars than planets, although it makes much more sense to think of them as planets, since they orbit the sun.

    October 15, 2007

  • "What is the use of a house if you haven't got a tolerable planet to put it on?" - Henry David Thoreau

    December 11, 2007

  • '"And yesterday the planet seemed to be going so well..."' -The Hitchhiker's Guide to the Galaxy, by Douglas Adams

    February 18, 2008

  • Planets in astrology have a different meaning to the modern astronomical understanding of what a planet is. Astrology utilises the ancient geocentric model of the universe in its calculations and thus employs the term in its original geocentric sense. Before the age of telescopes, the night sky was observed to consist of two very similar components: fixed stars, which remained motionless in relation to each other, and wandering stars, (in ancient Greek: asteres planetai) which appeared to shift their positions relative to the fixed stars over the course of the year. To the Greeks and the other earliest astronomers, this group comprised the five planets visible to the naked eye and excluded the earth. Although strictly the term "planet" applied only to those five objects, the term was latterly broadened, particularly in the Middle Ages, to include the Sun and the Moon (sometimes referred to as "Lights"), making a total of seven planets. Astrologers retain this definition today.


    February 24, 2008

  • To let someone tell you Pluto is not a planet is to let some pedant make arbitrary decisions about what words mean and do not mean.
    A nut used to be a hard shelled thing. And the botanists came by and told us that "Walnuts are not nuts, they are drupes." 

    Here they are, in the 1800's, after discovering Ceres, acknowledging  the Greek definition, but then trying to 'redefine' the word to suit themselves.  and then in 2006, they try to redefine the word again and when someone tries to call Pluto a planet, it's met with scorn from a pedant who gets hung up on a revision of a revision while ignoring the usage of the word that people have had for thousands of years.

    Someone replied to me with a 'Well, if Pluto is a planet, then the moon should be a planet too because it's the same size.'.   Well, the funny thing is, Luna used to be called a planet.

    It's hard to take the pedants seriously when they focus on redefining existing words all the time.
    It's just as bad as the botanists telling us that walnuts are not nuts.

    edit- walnuts, not peanuts.

    July 16, 2015

  • Really? A botanist called a peanut a drupe? All the botanists I know say a peanut is a legume. A drupe is a stone fruit with a fleshy covering over the seed, including peaches, plums and many others.

    July 16, 2015

  • thsnks slumry, it's walnuts that are 'drupes'.

    July 16, 2015

  • n. A star, as influencing the fate of a men.

    Of a men...

    -from the GNU version of the Collaborative International Dictionary of English.

    July 17, 2015

  • There's no problem with calling Pluto a planet. The problem is with the pedants who insist that there are nine planets, for no good reason except that this was what was true when they were growing up. No doubt many people who grew up between 1846 and 1930 felt the same about the absurd claim that there was a ninth planet: that titchy thing? Give me a break.

    Let Pluto be a planet. You're then committed (both linguistically and scientifically) to saying Quaoar, Sedna, Orcus, Eris, Varuna, Haumea, and Makemake are planets, to name just the more prominent named ones. When I was growing up there were 103 elements and I learnt them all. I have resisted the urge to tell scientists they're not allowed to discover any more.

    If they're not allowed to demote anything because pedants don't like it, then they weren't allowed to demote the planet Ceres, or the planets such as Juno and Vesta discovered in quick succession after it.

    July 17, 2015

  • The problem is that the word is re-defined every time someone gets a shinier newer telescope and sees new things, and they go around telling everyone else how 'wrong' they are because they redefined a word for themselves.

    We created the word asteroid for all the items in the asteroid belt, but we haven't done that for the oort cloud and the Kuiper belt.

    They use clumsy words like TNO Trans Neptunian Objects , KBO Kuiper Belt Objects, and the useless phrase Dwarf Planet which doens't tell a listener much other than the size of the object.

    We've created words like Centaurs and Trojans to classify objects, and those words tell a scientist where those objects are and what their orbit is, but once you get past Neptune, the language turns awkward and we let awkward scientists redefine the language.

    Where are these 'Dwarf Planets'? Some are in the asteroid belt, some in the Kuiper belt, and one has an orbit which is in resonance with Neptune and crosses Neptune's orbit.

    dwarf planet is a poor descriptor of an object. It's the astronomical version of 'thingy' or 'thingamajig'. It's like going into a toolbox and having wrenches, pliers, screwdrivers, and calling everthing else a 'gizmo'.

    It's lazy. It's not even a good scientific categorization.

    If the astronomers want to create a new label, they should pick a label that tells a person what it is that they're looking at. dwarf planet is the scientific equivalent of gizmo; you're not really categorizing something.

    July 17, 2015