According to the "Oxford English Dictionary", a shaman ( , or ) is someone who is regarded as having access to, and influence in, the world of benevolent and malevolent spirits, who typically enters into a trance state during a ritual, and practices divination and healing. The word "shaman" probably originates from the Tungusic Evenki language of North Asia. According to ethnolinguist Juha Janhunen, "the word is attested in all of the Tungusic idioms" such as Negidal, Lamut, Udehe/Orochi, Nanai, Ilcha, Orok, Manchu and Ulcha, and "nothing seems to contradict the assumption that the meaning 'shaman' also derives from Proto-Tungusic" and may have roots that extend back in time at least two millennia. The term was introduced to the west after Russian forces conquered the shamanistic Khanate of Kazan in 1552.