ostracism

-noun [Fr. ostracisme, from Lat. ostracismus, from Gr. ostrakismos = ostracism (see below); ostrakiso = to ostracise, from ostrakon = a polished shell of a mollusc.]

1. Lit: A practice introduced into Athens by Kleisthenes to preserve the democratic government which had established, and which sooner or later existed also in Argos, Megara, Miletus, and Syracuse. If any citizen became so powerful that it was feared he would attempt to overthrow the government, an ostracism was asked from the Athenian senate and the public assembly. If granted the citizens each deposited a shell or potsherd (broken piece of ceramic) on which was written the name of any person of whom they entertained apprehensions, and if 6,000 concurred in voting against the same individual, he was required to go into honourable banishment for ten years, retaining, however, all his property.

2. Fig. Banishment from society, exclusion from society; expulsion.

References - Universal Dictionary of the English Language, Robert Hunter and Charles Morris, 1898. 3401.