Precession

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Precession \Pre*ces"sion\, n. [L. praecedere, praecessum, to go
     before: cf. F. pr['e]cession. See {Precede}.]
     The act of going before, or forward.
     [1913 Webster]
  
     {Lunisolar precession}. (Astron.) See under {Lunisolar}.


  
     {Planetary precession}, that part of the precession of the
        equinoxes which depends on the action of the planets
        alone.
  
     {Precession of the equinoxes} (Astron.), the slow backward
        motion of the equinoctial points along the ecliptic, at
        the rate of 50.2[sec] annually, caused by the action of
        the sun, moon, and planets, upon the protuberant matter
        about the earth's equator, in connection with its diurnal
        rotation; -- so called because either equinox, owing to
        its westerly motion, comes to the meridian sooner each day
        than the point it would have occupied without the motion
        of precession, and thus precedes that point continually
        with reference to the time of transit and motion.
        [1913 Webster]

From WordNet (r) 2.0 [wn]:

  precession
       n 1: the motion of a spinning body (as a top) in which it wobbles
            so that the axis of rotation sweeps out a cone
       2: the act of preceding in time or order or rank (as in a
          ceremony) [syn: {precedence}, {precedency}]