What is "uriankhai"

Uriankhai (also written as "Uriyangkhai", "Urianhai", or "Uryangkhai") is a Mongolian term applied to several neighboring "forest" ethnic groups such as the Altai Uriankhai, Tuvans and Yakuts. The Uriankhai have been mentioned in medieval Chinese sources since the 10th century and the name appears several times in The Secret History of the Mongols. It is recorded in Chinese as Wulianghai or Wuliangha .