os·tra·con noun oros·tra·kon\ˈästrəˌkän\ (pluralostra·caorostra·ka \-rə̇kə\) Etymology: Greek ostrakon 1.: a potsherd used as a ballot in the ancient Athenian practice of ostracism 2.: a fragment of pottery or limestone containing a written inscription < that the Hebrews … wrote freely on papyrus, parchment and potsherds is apparent from large finds of ostraca — I.M.Price >