Emily Dickinson Lexicon

OS'TRA-CISM, n. [Gr. οστρακισμος, from οστρακον, a shell, or potter's ware.]

1. In Grecian antiquity, banishment by the people of Athens, of a person whose merit and influence gave umbrage to them. It takes this name from the shell on which the name or the note of acquittal or condemnation was written. It is however most probable that this shell was a piece of baked earth, rendered by the Latins testa. – Encyc.
2. Banishment; expulsion; separation. Sentenced to a perpetual ostracism from the esteem and confidence, and honors and emoluments of his country. – Federalist, Hamilton.