Oxus: Greek name of a river in Central-Asia, now known as Amudar'ya.
The sources of this stream are on the western slopes of the Pamir mountain range, where the ancient Silk road crossed into China.The Upper Oxus flows from the east to the west and separated Bactria (northern Afghanistan) from Sogdia (modern Uzbekistan and parts of Tajikistan), which has also been called Transoxiana.
Beyond Bactria, the river turns to the northwest. It divides two deserts, the Kara Kum (the "black desert", to the southwest) and the Kizil Kum (the "red desert", to the northeast). The waters were not used for irrigation, nor were there many palms along the river; unlike the Nile, Euphrates, or Tigris, the Oxus was something of an intrusion in a desert landscape.The delta immediately south of Lake Aral used to be called Chorasmia. Here, the waters were heavily used to irrigate the land. It is possible that in Antiquity one of its branches continued to the Caspian Sea.note[Herodotus, Histories 1.202; he confuses the Oxus with the Araxes.]
Not far from its sources, Alexander the Great (or his friend Hephaestion, to be more precise) founded the city of Alexandria, which controlled the trade in lapis lazuli.