Source : Webster's Revised Unabridged Dictionary (1913)

Pivot \Piv"ot\, n. [F.; prob. akin to It. piva pipe, F. pipe.
   See {Pipe}.]
   1. A fixed pin or short axis, on the end of which a wheel or
      other body turns.

   2. The end of a shaft or arbor which rests and turns in a
      support; as, the pivot of an arbor in a watch.

   3. Hence, figuratively: A turning point or condition; that on
      which important results depend; as, the pivot of an
      enterprise.

   4. (Mil.) The officer or soldier who simply turns in his
      place whike the company or line moves around him in
      wheeling; -- called also {pivot man}.

   {Pivot bridge}, a form of drawbridge in which one span,
      called the pivot span, turns about a central vertical
      axis.

   {Pivot gun}, a gun mounted on a pivot or revolving carriage,
      so as to turn in any direction.

   {Pivot tooth} (Dentistry), an artificial crown attached to
      the root of a natural tooth by a pin or peg.

Pivot \Piv"ot\, v. t. [imp. & p. p. {Pivoted}; p. pr. & vb. n.
   {Pivoting}.]
   To place on a pivot. --Clarke.

Source : WordNet®

pivot
     n 1: the person in a rank around whom the others wheel and
          maneuver [syn: {pivot man}]
     2: axis consisting of a short shaft that supports something
        that turns [syn: {pin}]
     3: the act of turning on (or as if on) a pivot; "the golfer
        went to the driving range to practice his pivot"

pivot
     v : turn on a pivot [syn: {swivel}]