The Collaborative International Dictionary of English v.0.48:

Fulcrum \Ful"crum\, n.; pl. L. Fulcra, E. Fulcrums. [L.,
   bedpost, fr. fulcire to prop.]
   [1913 Webster]
   1. A prop or support.
      [1913 Webster]

   2. (Mech.) That by which a lever is sustained, or about which
      it turns in lifting or moving a body.
      [1913 Webster]

   3. (Bot.) An accessory organ such as a tendril, stipule,
      spine, and the like. [R.] --Gray.
      [1913 Webster]

   4. (Zool.)
      (a) The horny inferior surface of the lingua of certain
          insects.
      (b) One of the small, spiniform scales found on the front
          edge of the dorsal and caudal fins of many ganoid
          fishes.
          [1913 Webster]

   5. (Anat.) The connective tissue supporting the framework of
      the retina of the eye.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fulcrum
    n 1: the pivot about which a lever turns

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "fulcrum":
   advocate, alpenstock, arbor, arm, athletic supporter, axis, axle,
   axle bar, axle shaft, axle spindle, axle-tree, back, backbone,
   backing, bandeau, bearer, bearing, bra, brace, bracer, bracket,
   brassiere, buttress, cane, carrier, cervix, corset, crook, crutch,
   distaff, foundation garment, gimbal, girdle, gudgeon, guy, guywire,
   hinge, hingle, hub, jock, jockstrap, mainstay, maintainer, mandrel,
   mast, nave, neck, oarlock, pin, pintle, pivot, pole, prop, radiant,
   reinforce, reinforcement, reinforcer, rest, resting place,
   resting point, rigging, rowlock, shoulder, shroud, spindle, spine,
   sprit, staff, standing rigging, stave, stay, stick, stiffener,
   strengthener, support, supporter, sustainer, swivel, thole,
   tholepin, trunnion, upholder, walking stick