East Turkestan or East Turkistan, also called Uyghuristan, is a loosely-defined geographical region in the northwestern part of the People's Republic of China, which varies in meaning by context and usage. The term was coined in the 19th century by Russian Turkologists, including Nikita Bichurin, who intended the name to replace the common Western term for the region, "Chinese Turkestan", which referred to the Tarim Basin in Southern Xinjiang or Xinjiang as a whole during the Qing dynasty. Beginning in the 17th century, Altishahr, which means "Six Cities" in Uyghur, became the Uyghur name for the Tarim Basin. Uyghurs also called the Tarim Basin "Yettishar," which means "Seven Cities," and even "Sekkizshahr", which means "Eight Cities" in Uyghur. Chinese dynasties from the Han dynasty to the Tang dynasty had called an overlapping area the "Western Regions".

Nikita Yakovlevich Bichurin, better known under his archimandrite monastic name Hyacinth, sometimes Joacinth or Iakinf, was one of the founding fathers of Russian Sinology. He translated many works from Chinese into Russian, which were then translated into other European languages.