The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. The end of a shaft or arbor which rests and turns in a
      support; as, the pivot of an arbor in a watch.
      [1913 Webster]

   3. Hence, figuratively: A turning point or condition; that on
      which important results depend; as, the pivot of an
      enterprise.
      [1913 Webster]

   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.
      [1913 Webster]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pivot \Piv"ot\, v. t. [imp. & p. p. Pivoted; p. pr. & vb. n.
   Pivoting.]
   To place on a pivot. --Clarke.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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

Moby Thesaurus II by Grady Ward, 1.0:

175 Moby Thesaurus words for "pivot":
   ankle, arbor, articulation, avert, axis, axle, axle bar,
   axle shaft, axle spindle, axle-tree, bearing, bench mark, boundary,
   butt, cardinal point, center, center of action, center of gravity,
   centroid, centrum, cervix, chief thing, circle, circulate,
   circumrotate, circumvolute, climax, clinch, closure, come about,
   connecting link, connecting rod, connection, core, cornerstone,
   coupling, crank, crisis, critical point, crux, dead center,
   deflect, depend, distaff, divert, dovetail, elbow, embrace,
   epicenter, essence, essential, essential matter, fetch about,
   focal point, fulcrum, fundamental, gimbal, gist, gliding joint,
   go about, go around, go round, gravamen, great point, gudgeon,
   gyrate, gyre, hang, heart, heel, high point, hinge, hinged joint,
   hingle, hip, hub, important thing, interface, issue, join, joining,
   joint, juncture, kernel, keystone, kingpin, knee, knuckle,
   landmark, link, main point, main thing, mandrel, marrow,
   material point, meat, medulla, metacenter, middle, milestone,
   miter, mortise, nave, navel, neck, nub, nucleus, oarlock, omphalos,
   pin, pintle, pirouette, pith, pivot about, pivot joint, pole,
   put about, rabbet, radiant, real issue, rely, rest, resting point,
   revolve, rotate, round, rowlock, salient point, scarf, screw, seam,
   sheer, shoulder, sine qua non, spin, spindle, stitch, storm center,
   substance, substantive point, suture, swing, swing round, swivel,
   symphysis, the bottom line, the point, thole, tholepin, tie rod,
   toggle, toggle joint, trunnion, turn, turn a pirouette, turn about,
   turn around, turn round, turn tail, turning point, twirl, twist,
   umbilicus, union, veer, veer around, volte-face, wamble, weld,
   wheel, wheel about, whip, whirl, wind, wrist