2. fragment of such a vessel, potsherd, IG42(1).121.82 (Epid., iv B. C., pl.), LXX Ps.21.16, al., Ostr.1152, etc.; “ἰπνοῦ ὄστρακα” Hp.Morb.2.47; esp. the potsherd used in voting (v. ὀστρακίζω): hence τοὔστρακον παροίχεται the danger of ostracism is past, Cratin.71; τὰ ὄστρακα, = ὀστρακισμός, Pl.Com.187; τὸ ὄ. ἐπιφέρειν τινί to vote for any one's banishment, Plu.Alc.13, cf. Per. 14.
3. ὀστράκου περιστροφή, of the game ὀστρακίνδα (q. v.), Pl. R.521c; so ὀστράκου μεταπεσόντος 'if heads become tails', Id.Phdr. 241b.
II. the hard shell of snails, mussels, cuttle-fishes, tortoises, etc., h.Merc.33, S.Ichn.303 (dub.l.), Hp.Steril.245, Theoc.9.25, Arist.HA528a4, etc.: hence, tortoise-shell or mother-of-pearl, κλιντῆρες ὀστράκοις . . ἐνδεδεμένοι prob. l. in Ph. 1.666; the shell at the base of the constellation Lyra, Ptol.Alm. 7.5.