planet wheel

2 definitions found

planet wheel - Collaborative International Dictionary of English v.0.48 :

  Planet \Plan"et\, n. [OE. planete, F. plan[`e]te, 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.
        [1913 Webster]
  
     Note: 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.
           [1913 Webster]
  
     2. A star, as influencing the fate of a men.
        [1913 Webster]
  
              There's some ill planet reigns.       --Shak.
        [1913 Webster]
  
     Planet gear. (Mach.) See Epicyclic train, under
        Epicyclic.
  
     Planet wheel, a gear wheel which revolves around the wheel
        with which it meshes, in an epicyclic train.
        [1913 Webster]

planet wheel - WordNet (r) 2.1 (2005) :

  planet wheel
      n 1: an outer gear that revolves about a central sun gear of an
           epicyclic train [syn: planetary gear, epicyclic gear,
           planet wheel, planet gear]