The Collaborative International Dictionary of English v.0.48:

Expectation \Ex`pec*ta"tion\n. [L. expectio. exspectio: cf. F.
   expectation.]
   1. The act or state of expecting or looking forward to an
      event as about to happen. "In expectation of a guest."
      --Tennyson.
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            My soul, wait thou only upon God, for my expectation
            is from him.                          --Ps. lxii. 5.
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   2. That which is expected or looked for.
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            Why our great expectation should be called
            The seed of woman.                    --Milton.
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   3. The prospect of the future; grounds upon which something
      excellent is expected to happen; prospect of anything good
      to come, esp. of property or rank.
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            His magnificent expectations made him, in the
            opinion of the world, the best match in Europe.
                                                  --Prescott.
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            By all men's eyes a youth of expectation. --Otway.
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   4. The value of any chance (as the prospect of prize or
      property) which depends upon some contingent event.
      Expectations are computed for or against the occurrence of
      the event.
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   5. (Med.) The leaving of the disease principally to the
      efforts of nature to effect a cure.
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   Expectation of life, the mean or average duration of the
      life individuals after any specified age.

   Syn: Anticipation; confidence; trust.
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WordNet (r) 3.0 (2006):

expectation
    n 1: belief about (or mental picture of) the future [syn:
         expectation, outlook, prospect]
    2: anticipating with confidence of fulfillment [syn:
       anticipation, expectation]
    3: the feeling that something is about to happen
    4: the sum of the values of a random variable divided by the
       number of values [syn: arithmetic mean, first moment,
       expectation, expected value]

Moby Thesaurus II by Grady Ward, 1.0:

127 Moby Thesaurus words for "expectation":
   aftertime, afteryears, anticipation, apprehension,
   apprehensiveness, aptitude, aspiration, assumption, assurance,
   assured faith, awelessness, belief, by-and-by, calmness, chance,
   cheerful expectation, composure, confidence, conjecture,
   conviction, cool, coolness, course ahead, crystal ball, demand,
   dependence, design, desire, determinism, distant future,
   doomed hope, dueness, entitledness, entitlement, eventuality,
   expectancy, fair expectation, fair prospect, faith,
   favorable prospect, fervent hope, foresight, forward look, future,
   future tense, futurism, futurity, good chance, good cheer,
   good hope, great expectations, guess, hereafter, high hopes, hope,
   hopeful prognosis, hopefulness, hopes, hoping, hoping against hope,
   immediate future, immediate prospect, imminence, inexcitability,
   insistence, intention, justice, justifiable expectation, liability,
   likelihood, likeliness, meritedness, motive, near future,
   nodding acceptance, nonamazedness, nonamazement, nonastonishment,
   nonmarveling, nonwonder, nonwondering, notion, odds, offing,
   outlook, posteriority, prayerful hope, prediction, presumption,
   presumptive evidence, probabilism, probability, project, promise,
   prophecy, prospect, prospects, reasonable ground, reasonable hope,
   reliance, requirement, sanguine expectation, security, supposition,
   surmise, suspense, tendency, the future, the morrow,
   the sweet by-and-by, time ahead, time just ahead, time to come,
   tomorrow, trust, unamazedness, unamazement, unastonishment,
   unimpressibleness, unsurprise, unsurprisedness, verisimilitude,
   want, watchfulness, well-grounded hope, wish, wonderlessness



Bouvier's Law Dictionary, Revised 6th Ed (1856):

EXPECTATION. That which may be expected, although contingent. In the
doctrine of life annuities, that share or number of the years of human life
which a person of a given age may expect to live, upon an equality of
chances.
     2. In general, the heir apparent will be relieved from a contract made
in relation to his expectancy. See Post Obit.