The Collaborative International Dictionary of English v.0.48:

Reality \Re*al"i*ty\ (r[-e]*[a^]l"[i^]*t[y^]), n.; pl.
   Realities (-t[i^]z). [Cf. F. r['e]alit['e], LL. realitas.
   See 3d Real, and cf. 2d Realty.]
   1. The state or quality of being real; actual being or
      existence of anything, in distinction from mere
      appearance; fact.
      [1913 Webster]

            A man fancies that he understands a critic, when in
            reality he does not comprehend his meaning.
                                                  --Addison.
      [1913 Webster]

   2. That which is real; an actual existence; that which is not
      imagination, fiction, or pretense; that which has
      objective existence, and is not merely an idea.
      [1913 Webster]

            And to realities yield all her shows. --Milton.
      [1913 Webster]

            My neck may be an idea to you, but it is a reality
            to me.                                --Beattie.
      [1913 Webster]

   3. [See 1st Realty, 2.] Loyalty; devotion. [Obs.]
      [1913 Webster]

            To express our reality to the emperor. --Fuller.
      [1913 Webster]

   4. (Law) See 2d Realty, 2.
      [1913 Webster]

WordNet (r) 3.0 (2006):

reality
    n 1: all of your experiences that determine how things appear to
         you; "his world was shattered"; "we live in different
         worlds"; "for them demons were as much a part of reality as
         trees were" [syn: world, reality]
    2: the state of being actual or real; "the reality of his
       situation slowly dawned on him" [syn: reality, realness,
       realism] [ant: irreality, unreality]
    3: the state of the world as it really is rather than as you
       might want it to be; "businessmen have to face harsh
       realities"
    4: the quality possessed by something that is real [ant:
       unreality]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "reality":
   accomplished fact, actuality, adventure, authenticity,
   circumstance, confirmability, demonstratability, doubtlessness,
   entelechy, episode, eternal verities, event, experience, fact,
   factuality, fait accompli, genuineness, good sooth, grim reality,
   hap, happening, happenstance, historical truth, historicity,
   in reality, incident, incontestability, incontrovertibility,
   indisputability, indubitability, indubitableness, irrefragability,
   irrefutability, materiality, matter of fact, not a dream,
   objective existence, occasion, occurrence, particular, phenomenon,
   provability, questionlessness, really, sooth, the true, trueness,
   truth, truthfulness, turn of events, ultimate truth,
   unconfutability, undeniability, unerroneousness, unfallaciousness,
   unfalseness, unimpeachability, unquestionability, unrefutability,
   veracity, verifiability, verity, very truth



The Devil's Dictionary (1881-1906):

REALITY, n.  The dream of a mad philosopher.  That which would remain
in the cupel if one should assay a phantom.  The nucleus of a vacuum.