Planet
Pronunciation
- UK IPA: /ˈplanɪt/
- US IPA: /ˈplænət/
- Rhymes: -ænɪt
Origin
From Middle English planete, from Old English planÄ“ta ("planet, chasuble"), from Latin planeta, planetes, from Ancient Greek πλανήτης variant of πλάνης (planÄ“s, "wanderer, planet"), from Ancient Greek πλανάω (planáÅ, "wander about, stray"), of unknown origin. Perhaps from a Proto-Indo-European *pel- ("to wander, roam"), cognate with Latin pÄlor ("wander about, stray"), Old Norse flana ("to rush about"), Norwegian flanta ("to wander about"). More at flaunt.
Full definition of planet
Noun
planet
(plural planets)- (now historical or astrology) Each of the seven major bodies which move relative to the fixed stars in the night sky—the Moon, Mercury, Venus, the Sun, Mars, Jupiter and Saturn. from 14th c.
- 1603, John Florio, translating Michel de Montaigne, Essays, II.12:Be they not dreames of humane vanity, ... to make of our knowne earth a bright shining planet ?
- 1749, Henry Fielding, Tom Jones, Folio Society 1973, p. 288:The moon...began to rise from her bed, where she had slumbered away the day, in order to sit up all night. Jones had not travelled far before he paid his compliments to that beautiful planet, and, turning to his companion, asked him if he had ever beheld so delicious an evening?
- 1971, Keith Thomas, Religion and the Decline of Magic, Folio Society 2012, p. 361:Another of Boehme's followers, the Welshman Morgan Llwyd, also believed that the seven planets could be found within man.
- (astronomy) A body which orbits the Sun directly and is massive enough to be in hydrostatic equilibrium (effectively meaning a spheroid) and to dominate its orbit; specifically, the eight major bodies of Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. (Pluto was considered a planet until 2006 and has now been reclassified as a dwarf planet.) from 17th c.
- 1640, John Wilkins, (title):A Discovrse concerning a New Planet. Tending to prove, That 'tis probable our Earth is one of the Planets.
- 2006, Alok Jha, The Guardian, 22 Dec 2006:Their decision will force a rewrite of science textbooks because the solar system is now a place with eight planets and three newly defined "dwarf planets" - a new category of object that includes Pluto.
- A large body which directly orbits any star (or star cluster) but which has not attained nuclear fusion.
- In phrases such as the planet, this planet, sometimes refers to the Earth.
- 1907, Robert W. Chambers, The Younger Set Chapter 8, “ My tastes,†he said, still smiling, “ incline me to the garishly sunlit side of this planet.†And, to tease her and arouse her to combat : “ I prefer a farandole to a nocturne ; I'd rather have a painting than an etching ; … â€
- 2013-06-07, David Simpson, Fantasy of navigation, It is tempting to speculate about the incentives or compulsions that might explain why anyone would take to the skies in the basket a balloon: …; perhaps to moralise on the oneness or fragility of the planet, or to see humanity for the small and circumscribed thing that it is; ….
Usage notes
The term planet originally meant any star which wandered across the sky, and generally included comets and the Sun and Moon. With the Copernican revolution, the Earth was recognized as a planet, and the Sun was seen to be fundamentally different. The Galileian satellites of Jupiter were at first called planets (satellite planets), but later reclassified along with the Moon. The first asteroids were also thought to be planets, but were reclassified when it was realized that there were a great many of them, crossing each other's orbits, in a zone where only a single planet had been expected. Likewise, Pluto was found where an outer planet had been expected, but doubts were raised when it turned out to cross Neptune's orbit and to be much smaller than the expectation required. When Eris, an outer body more massive than Pluto, was discovered, the International Astronomical Union (IAU) officially defined the word "planet" as above. However, a significant minority have refused to accept the IAU definition. Many simply continue with the nine planets that had been recognized prior to the discovery of Eris. Others are of the opinion that orbital parameters should be irrelevant, and that any equilibrium (≈ spherical) body in orbit around a star is a planet; there are likely several hundred such bodies in the Solar system. Still others argue that orbiting a star should also be irrelevant, thus re-accepting the Galileian satellites (as well as a dozen other moons) as planets.
Note that the 2006 IAU definition defines a planet in respect to the Sun, and is thus technically inapplicable to exoplanets.