Source : Webster's Revised Unabridged Dictionary (1913)

Expiation \Ex`pi*a"tion\, n. [L. expiatio: cf.F. expiation]
   1. The act of making satisfaction or atonement for any crime
      or fault; the extinguishing of guilt by suffering or
      penalty.

            His liberality seemed to have something in it of
            self-abasement and expiation.         --W. Irving.

   2. The means by which reparation or atonement for crimes or
      sins is made; an expiatory sacrifice or offering; an
      atonement.

            Those shadowy expiations weak, The blood of bulls
            and goats.                            --Milton.

   3. An act by which the treats of prodigies were averted among
      the ancient heathen. [Obs.] --Hayward.

Source : WordNet®

expiation
     n 1: compensation for a wrong; "we were unable to get
          satisfaction from the local store" [syn: {atonement}, {satisfaction}]
     2: the act of atoning for sin or wrongdoing (especially
        appeasing a deity) [syn: {atonement}, {propitiation}]