The word "ostracon" is derived from the Greek "ostrakon" (meaning a piece of pottery used as a voting ballot). When a vote was held on whether to banish a person from society these shards were used to cast votes. This is the origin of the word "ostracism" (literally meaning "to be voted out").
In ancient Egypt ostracon (plural ostraca) were of a more general use. Pieces of broken pottery or stone (most often limestone) were used as notepads as they were a cheaper and more plentiful option than papyrus which was costly and time consuming to make. Ostraca were used by students in scribal schools to practice their writing and by administrators to write notes, keep tallies of goods and calculate taxation. They were used to scribble messages and draw preparatory sketches for artworks. The ancient Egyptians also used them to make votive offerings to gods and to the deceased.
While many ostraca were small and carried only brief notes or pictures, some were fairly large. A large ostracon inscribed with the The Story of Sinuhe was found in the tomb of the craftsman Sennedjem at Deir el Medina and thousands of sketches in black and red ink on large limestone flakes were discovered in the workman's village near Deir el-Medina. These sketches seem to have been the work of craftsmen from the Ramesside Period who excavated and decorated the tombs in the Valley of the Kings. Many similar pieces were found near the notably the mortuary temple of Hatshepsut and the mortuary temple of Thutmose III at Deir el-Bahri.
Ostraca from Deir el Medina also provide a fascinating glimpse of medical care in ancient Egypt. Injury or illness was dealt with by a combination of medical treatment, prayer and magic. Physicians would prescribe treatments which they most likely mixed themselves following recipes noted on ostraca, but some requests for ingredients may also relate to remedies mixed at home by the patient or their families. Magical spells could be employed by specialist practicioners (in the case of snake bite or scorpion stings) or passed on ostraca from one worker to another without the involvement of any specialist.
Another interesting find is from a catacomb in Saqqara which contained (in addition to numerous other smaller ostraca) a series of records known as the "Dream Ostraca". These record the dreams of clients who visited Hor of Sebennytos, a scribe who offered guidance based on the interpretation of dreams.copyright J Hill 2010