potshard or limestone flake used in antiquity, especially by the ancient Egyptians, Greeks, and Hebrews, as a surface for drawings or sketches, or as an alternative to papyrus for writing as well as for calculating accounts. Of considerable artistic merit, the drawings on ostraca, which are usually coloured, depict scenes from nature and everyday life or scenes in which animals seem to parody human actions (it has been conjectured that the latter illustrated popular fables).