The Perso-Arabic Alphabet
The Persian variant of the Arabic alphabet is the foundation on which all other variants of the Arabic scripts were built. The Persians were the first non-Semitic people to be converted to Islam, so it was they who introduced the first and most widely adopted changes to the Arabic alphabet. Therefore, it is technically more correct to say that Pashto, Urdu and others use not the Arabic script but the Perso-Arabic script.