Petalism \Pet"al*ism\ (p[e^]t"al*[i^]z'm), n. [Gr. petalismo`s,
   fr. pe`talon a leaf: cf. F. p['e]talisme.] (Gr. Antiq.)
   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.
   [1913 Webster]