Английский Этимологический словарь - ostracism

- 1588, a method of 10-year banishment in ancient Athens, by which the citizens gathered and wrote the names of men they deemed dangerous to the state on potsherds or tiles, and a man whose name turned up often enough was sent away. From Gk. ostrakismos, from ostrakizein "to ostracize," from ostrakon "tile, potsherd," related to osteon "bone," ostreion "oyster." A similar practice in ancient Syracuse (with banishment for five years) was by writing names on olive leaves, and thus was called petalismos.