The Collaborative International Dictionary of English v.0.48:

Sensation \Sen*sa"tion\, n. [Cf. F. sensation. See Sensate.]
   1. (Physiol.) An impression, or the consciousness of an
      impression, made upon the central nervous organ, through
      the medium of a sensory or afferent nerve or one of the
      organs of sense; a feeling, or state of consciousness,
      whether agreeable or disagreeable, produced either by an
      external object (stimulus), or by some change in the
      internal state of the body.
      [1913 Webster]

            Perception is only a special kind of knowledge, and
            sensation a special kind of feeling. . . . Knowledge
            and feeling, perception and sensation, though always
            coexistent, are always in the inverse ratio of each
            other.                                --Sir W.
                                                  Hamilton.
      [1913 Webster]

   2. A purely spiritual or psychical affection; agreeable or
      disagreeable feelings occasioned by objects that are not
      corporeal or material.
      [1913 Webster]

   3. A state of excited interest or feeling, or that which
      causes it.
      [1913 Webster]

            The sensation caused by the appearance of that work
            is still remembered by many.          --Brougham.
      [1913 Webster]

   Syn: Perception.

   Usage: Sensation, Perseption. The distinction between
          these words, when used in mental philosophy, may be
          thus stated; if I simply smell a rose, I have a
          sensation; if I refer that smell to the external
          object which occasioned it, I have a perception. Thus,
          the former is mere feeling, without the idea of an
          object; the latter is the mind's apprehension of some
          external object as occasioning that feeling.
          "Sensation properly expresses that change in the state
          of the mind which is produced by an impression upon an
          organ of sense (of which change we can conceive the
          mind to be conscious, without any knowledge of
          external objects). Perception, on the other hand,
          expresses the knowledge or the intimations we obtain
          by means of our sensations concerning the qualities of
          matter, and consequently involves, in every instance,
          the notion of externality, or outness, which it is
          necessary to exclude in order to seize the precise
          import of the word sensation." --Fleming.
          [1913 Webster]

WordNet (r) 3.0 (2006):

sensation
    n 1: an unelaborated elementary awareness of stimulation; "a
         sensation of touch" [syn: sensation, esthesis,
         aesthesis, sense experience, sense impression, sense
         datum]
    2: someone who is dazzlingly skilled in any field [syn: ace,
       adept, champion, sensation, maven, mavin,
       virtuoso, genius, hotshot, star, superstar, whiz,
       whizz, wizard, wiz]
    3: a general feeling of excitement and heightened interest;
       "anticipation produced in me a sensation somewhere between
       hope and fear"
    4: a state of widespread public excitement and interest; "the
       news caused a sensation"
    5: the faculty through which the external world is apprehended;
       "in the dark he had to depend on touch and on his senses of
       smell and hearing" [syn: sense, sensation, sentience,
       sentiency, sensory faculty]

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "sensation":
   affect, affection, amazement, astonishing thing, astonishment,
   awareness, bang, bean, best seller, big hit, bomb, bombshell, boot,
   brain, brilliant success, charge, commotion, consciousness,
   curiosity, emotion, emotional charge, emotional shade, encephalon,
   exception, excitement, experience, fad, feeling, feeling tone,
   flush, foreboding, funny feeling, gas, gasser, gazingstock,
   gray matter, great success, gut reaction, head, heartthrob, hit,
   hunch, impression, jollies, kick, killing, lift, marvel,
   marvelment, meteoric success, miracle, momentary success, noddle,
   noggin, nonesuch, noodle, organ of thought, passion, pate,
   perception, phenomenon, portent, prescience, presentiment, prodigy,
   profound sense, quite a thing, quiver, rarity, reaction,
   resounding triumph, response, riot, roaring success, rush,
   rush of emotion, sconce, seat of thought, sense, sensibility,
   sensitiveness, sensitivity, sensorium, sensory, sentiment, shiver,
   shudder, sight, smash, smash hit, sneaking suspicion,
   something else, spectacle, stir, stunner, success,
   surge of emotion, susceptibility, suspicion, thrill, tingle,
   tingling, titillation, tremor, tremor of excitement, triumph,
   undercurrent, wonder, wonderful thing, wonderment, wow