Is Uber a unicorn?

Could you please elaborate on whether Uber can be classified as a unicorn company? What are the criteria typically used to determine if a company is a unicorn, and how does Uber fit into that definition? Are there any specific factors that make Uber stand out as a potential unicorn, or are there any challenges it faces that could hinder its status as such? Additionally, how does the valuation of Uber compare to other companies in its industry, and what impact does this have on its potential to be considered a unicorn?