Ostracism, banishment (lit. by shell) for a term of years by popular vote from Athens of any individual whose political influence seemed to threaten the liberty of the citizens; the vote was given by each citizen writing the name of the individual on a shell and depositing it in some place appointed, and it was only when supported by 6000 citizens that it took effect.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Ostia * Ostrogoths