'ostracize' originates from Greek, specifically the word 'ostrakizein', where 'ostrakon' meant 'potsherd (a piece of broken pottery)'; the practice involved voting with potsherds to banish a person.

'ostrakizein' passed into Late Latin and Medieval/Modern European usage and eventually entered English as 'ostracize' (also spelled 'ostracise' in British English).

Initially it meant 'to banish by voting with potsherds', but over time it evolved into the broader modern meaning 'to exclude, shun, or banish (socially or officially)'.