The Amu Darya (Persian: آمودریا, Âmudaryâ; Turkmen: Amyderýa/Амыдеря; Uzbek: Amudaryo/Амударё/ەمۇدەريا; Tajik: Амударё, Amudaryo; Pashto: د آمو سيند, də Āmú Sínd; Turkish: Ceyhun, Amu Derya; Ancient Greek: Ὦξος, Ôxos), also called the Amu River, is a major river in Central Asia.
In classical antiquity, the river was known as the Ōxus in Latin and Ὦξος Ôxos in Greek—a clear derivative of Vakhsh, the name of the largest tributary of the river. In Vedic Sanskrit, the river is also referred to as Vakṣu (वक्षु). The Brahmanda Purana refers to the river as Chaksu. The Avestan texts too refer to the River as Yakhsha/Vakhsha (and Yakhsha Arta ("upper Yakhsha") referring to the Jaxartes/Syr Darya twin river to Amu Darya).
Medieval Arabic and Muslim sources call the river Jayhoun (جيحون Jayḥūn; also Jaihun, Jayhoon, or Dzhaykhun) which is derived from Gihon, the biblical name for one of the four rivers of the Garden of Eden.