Proper noun
Arachosia
An Achaemenid and Seleucid satrapy in the eastern part of their respective empires, around modern-day southern Afghanistan.
Ancient references further The Arachosia Satrapy and the Pactyan people during the Achaemenid Empire in 500 B.C. A variety of ancient groups with eponyms similar to Pakhtun have been hypothesized as possible ancestors of modern Pashtuns. Source: Internet
British Museum The Indo-Scythians were descended from the Sakas (Scythians) who migrated from southern Siberia to Pakistan and Arachosia from the middle of the 2nd century BCE to the 1st century BCE. Source: Internet