Pahlavi is a particular, exclusively written form of various Middle Iranian languages. The essential characteristics of Pahlavi are: the use of a specific Aramaic-derived script; the incidence of Aramaic words used as heterograms (called hozwārishn, "archaisms"). Pahlavi compositions have been found for the dialects/ethnolects of Parthia, Persis, Sogdiana, Scythia, and Khotan. Independent of the variant for which the Pahlavi system was used, the written form of that language only qualifies as Pahlavi when it has the characteristics noted above. Pahlavi is then an admixture of: written Imperial Aramaic, from which Pahlavi derives its script, logograms, and some of its vocabulary. spoken Middle Iranian, from which Pahlavi derives its terminations, symbol rules, and most of its vocabulary. Pahlavi may thus be defined as a system of writing applied to (but not unique for) a specific language group, but with critical features alien to that language group. It has the characteristics of a distinct language, but is not one. It is an exclusively written system, but much Pahlavi literature remains essentially an oral literature committed to writing and so retains many of the characteristics of oral composition. Etymology The term Pahlavi is said to be derived from the Parthian language word parthav or parthau, meaning Parthia, a region just east of the Caspian Sea, with the -i suffix denoting the language and people of that region. If this etymology is correct, Parthav presumably became pahlaw through a semivowel glide rt (or in other cases rd) change to l, a common occurrence in language evolution (e.g. Arsacid sard became sal, zard>zal, vard>gol, sardar>salar etc.). The term has been traced back further to Avestan pərəthu- "broad [as the earth]", also evident in Sanskrit pŗthvi- "earth" and parthivi "[lord] of the earth". Common to all Indo-Iranian languages is a connotation of "mighty". History The earliest attested use of Pahlavi dates to the reign of Arsaces I of Parthia (250 BC) in early Parthian coins with Pahlavi scripts. There are also several Pahlavi texts written during the reign of Mithridates I (r. 171–138 BC). The cellars of the treasury at Mithradatkird (near modern-day Nisa) reveal thousands of pottery sherds with brief records; several ostraca that are fully dated bear references to members of the immediate family of the king. Such fragments, as also the rock inscriptions of Sassanid kings, which are datable to the 3rd and 4th centuries AD, do not, however, qualify as a significant