Source : Webster's Revised Unabridged Dictionary (1913)

Ostracism \Os"tra*cism\, n. [Gr. ?, fr. ? to ostracize. See
   {Ostracize}.]
   1. (Gr. Antiq.) Banishment by popular vote, -- a means
      adopted at Athens to rid the city of a person whose talent
      and influence gave umbrage.

   2. Banishment; exclusion; as, social ostracism.

            Public envy is as an ostracism, that eclipseth men
            when they grow too great.             --Bacon.

            Sentenced to a perpetual ostracism from the . . .
            confidence, and honors, and emoluments of his
            country.                              --A. Hamilton.

Source : WordNet®

ostracism
     n 1: the state of being banished or ostracized (excluded from
          society by general consent); "the association should get
          rid of its elderly members--not by euthanasia, of
          course, but by Coventry" [syn: {banishment}, {Coventry}]
     2: the act of excluding someone from society by general consent