Plan"et (?), n. [OE. planete, F. planète, L. planeta, fr. Gr. &?;, and &?; a planet; prop. wandering, fr. &?; to wander, fr. &?; a wandering.] 1. (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.

&fist; The term planet was first used to distinguish those stars which have an apparent motion through the constellations from the fixed stars, which retain their relative places unchanged. The inferior planets are Mercury and Venus, which are nearer to the sun than is the earth; the superior planets are Mars, the asteroids, Jupiter, Saturn, Uranus, and Neptune, which are farther from the sun than is the earth. Primary planets are those which revolve about the sun; secondary planets, or moons, are those which revolve around the primary planets as satellites, and at the same time revolve with them about the sun.

2. A star, as influencing the fate of a men.

There's some ill planet reigns.

• According to the , any of the objects Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto, regardless of finding a succinct definition that matches exactly these nine bodies without leaving any out or including other objects in the Solar system.
  
• A celestial object that: 1) Orbits the central star directly, not another body, 2) Is not massive enough to allow nuclear fusion in its core, 3) Is massive enough that its own gravity presses it into a roughly circular shape, 4) Is not part of a group of similar objects with overlapping orbits such as the asteroid belt.
  
• A by the International Astronomical Union states that a companion to a star that is smaller than required for the fusion of deuterium, estimated at 13 Jupiter masses is termed a planet. (But see usage note below).
  
• (Colloquial or Jargon) A celestial object that is like a planet, and unlike the typical moon etc., in one’s field of study, without concern as to its orbit. (See usage notes below.) Careful speakers use the term world instead.
  
  Swedish
• Large celestial body orbiting a star; see further discussion in the English entry
  
• definite singular of plan (see this word)