\Ec*cen"tric\, a. [F. excentrique, formerly also
spelled eccentrique, fr. LL. eccentros out of the center,
eccentric, Gr. ?; ? out of + ? center. See {Ex-}, and
{Center}, and cf. {Excentral}.]
1. Deviating or departing from the center, or from the line
   of a circle; as, an eccentric or elliptical orbit;
   pertaining to deviation from the center or from true
   circular motion.
2. Not having the same center; -- said of circles, ellipses,
   spheres, etc., which, though coinciding, either in whole
   or in part, as to area or volume, have not the same
   center; -- opposed to {concentric}.
3. (Mach.) Pertaining to an eccentric; as, the eccentric rod
   in a steam engine.
4. Not coincident as to motive or end.
         His own ends, which must needs be often eccentric to
         those of his master.                  --Bacon.
5. Deviating from stated methods, usual practice, or
   established forms or laws; deviating from an appointed
   sphere or way; departing from the usual course; irregular;
   anomalous; odd; as, eccentric conduct. ``This brave and
   eccentric young man.'' --Macaulay.
         He shines eccentric, like a comet's blaze. --Savage.
{Eccentric anomaly}. (Astron.) See {Anomaly}.
{Eccentric chuck} (Mach.), a lathe chuck so constructed that
   the work held by it may be altered as to its center of
   motion, so as to produce combinations of eccentric
   combinations of eccentric circles.
{Eccentric gear}. (Mach.)
   (a) The whole apparatus, strap, and other parts, by which
       the motion of an eccentric is transmitted, as in the
       steam engine.
   (b) A cogwheel set to turn about an eccentric axis used to
       give variable rotation.
{Eccentric} {hook or gab}, a hook-shaped journal box on the
   end of an eccentric rod, opposite the strap.
{Eccentric rod}, the rod that connects as eccentric strap
   with any part to be acted upon by the eccentric.
{Eccentric sheave}, or {Eccentric pulley}, an eccentric.
{Eccentric strap}, the ring, operating as a journal box, that
   encircles and receives motion from an eccentric; -- called
   also {eccentric hoop}.
Syn: Irregular; anomalous; singular; odd; peculiar; erratic;
     idiosyncratic; strange; whimsical.

\Ec*cen"tric\, n.
1. A circle not having the same center as another contained
   in some measure within the first.
2. One who, or that which, deviates from regularity; an
   anomalous or irregular person or thing.
3. (Astron.)
   (a) In the Ptolemaic system, the supposed circular orbit
       of a planet about the earth, but with the earth not in
       its center.
   (b) A circle described about the center of an elliptical
       orbit, with half the major axis for radius. --Hutton.
4. (Mach.) A disk or wheel so arranged upon a shaft that the
   center of the wheel and that of the shaft do not coincide.
   It is used for operating valves in steam engines, and for
   other purposes. The motion derived is precisely that of a
   crank having the same throw.
{Back eccentric}, the eccentric that reverses or backs the
   valve gear and the engine.
{Fore eccentric}, the eccentric that imparts a forward motion
   to the valve gear and the engine.