A form of sentence among the ancient Syracusans, by which they proscribed a citizen whose wealth or popularity alarmed their jealousy, or who was suspected of aspiring to sovereign power; temporary proscription, or banishment for five years. The mode was to give their votes by writing his name on a leaf. petalism in Syracuse answered to ostracism in Athens.

A form of sentence among the ancient Syracusans by which they banished for five years a citizen suspected of having dangerous influence or ambition. It was similar to the ostracism in Athens; but olive leaves were used instead of shells for ballots.