DICT.TW Dictionary Taiwan

Search for: [Show options]

[Pronunciation] [Help] [Database Info] [Server Info]

3 definitions found

From: Webster's Revised Unabridged Dictionary (1913)

 Plan·et n.
 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.
 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.
 2. A star, as influencing the fate of a men.
    There's some ill planet reigns.   --Shak.
 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.

From: Webster's Revised Unabridged Dictionary (1913)

 ep·i·cyc·lic, ep·i·cyc·lic·al a. Pertaining to, resembling, or having the motion of, an epicycle.
 Epicyclic train Mach., a train of mechanism in which epicyclic motion is involved; esp., a train of spur wheels, bevel wheels, or belt pulleys, in which an arm, carrying one or more of the wheels, sweeps around a center lying in an axis common to the other wheels.

From: WordNet (r) 2.0

 epicyclic train
      n : a system of epicyclic gears in which at least one wheel axis
          itself revolves about another fixed axis [syn: epicyclic
          gear train]