The ancient Athenians used a process to determine if a person was dangerous to the people or embarrassing to the state, which was through a vote. At the time, papyrus did not exist in Greece, and it was an imported material that was considered a luxury. Broken pottery was commonly found. In the spirit of the circular economy, they used this trash to undertake the vote. The name of the person who was scratched on shards of broken pottery was submitted. Those shards of broken pottery were known as Ostraka. These shards would be gathered by the thousands and tallied. After the tally, if a person was found to be dangerous, he would be banished from Athens.
The fact that ostraka were used to determine banishment turned the word into a verb, Ostrackismos, in Greek first. It then found its way into English in the form of Ostracise.