Many people refer to the people who were living in North America before Europeans as “Indians” and there’s even a good portion of those people that use it to self identify as well, even if “Native American” is more widely used, if not also somewhat an inaccurate if you’re getting technical.
In Russian language the difference between American and actual Indians is one letter in spelling (easily heard in pronunciation, so only small children maybe mix them up), historically it's a variation of the same word.
For "turkey" the bird the feminine version of the former is used (and not used to refer to an American Indian woman).
The point is, it's the main word to refer to Native Americans. "Настоящему индейцу завсегда везде ништяк" and all that.
Old worlder here. Still calling them Indians. Also actively refusing to use the term towards people of India, bexause we have other words for them (actually two, one similiar to Indian, secons not at all, neither a slur).