Early middle-ages (Old Uighur) ethnic connections of Baikal region with Central Asia (on example of ethnonyms Buin and Abazai)

The article reviews the semantics of names of the Buryat tribes buin and abazai, which are connected with Old-Uighur period of the Central Asian history. These ethnonyms are unique in the Central Asian region and found only among the Buryats, but not among the other Turkic-Mongolian peoples. Ethnonym abazai is etymological problem, since the two versions discussed in this article suggest its Turkic origin from the two areas, Yenisei area, or Central Asian area. In both cases it linked to the ancient Turkic (Uighur). To resolve the problem of the origin of the ethnonym buin the author presents a hypothesis associated with the rise of Buddhism in Uyghur Khaganate in the early Middle Ages. These two versions of the origin of the Buryat ethnonyms help to expand the humanitarian knowledge about ethnogenesis of the Buryats.