The Collaborative International Dictionary of English v.0.48:

Expectance \Ex*pect"ance\, Expectancy \Ex*pect"an*cy\, n.
   1. The act of expecting; expectation. --Milton.
      [1913 Webster]

   2. That which is expected, or looked or waited for with
      interest; the object of expectation or hope.
      [1913 Webster]

            The expectancy and rose of the fair state. --Shak.
      [1913 Webster]

   Estate in expectancy (Law), one the possession of which a
      person is entitled to have at some future time, either as
      a remainder or reversion, or on the death of some one.
      --Burrill.
      [1913 Webster]

WordNet (r) 3.0 (2006):

expectancy
    n 1: an expectation [syn: anticipation, expectancy]
    2: something expected (as on the basis of a norm); "each of them
       had their own anticipations"; "an indicator of expectancy in
       development" [syn: anticipation, expectancy]

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

EXPECTANCY, estates. Having a relation to or dependence upon something
future.
     2. Estates are of two sorts, either in possession, sometimes called
estates executed; or in expectancy, which are executory. Expectancies are,
first, created by the parties, called a remainder; or by act of law, called
a reversion.
     3. A bargain in relation to an expectancy is, in general, considered
invalid. 2 Ves. 157; Sel. Cas. in Ch. 8; 1 Bro. C. C. 10; Jer. Eq. Jur. 397.