Does the fact that it's a subsidiary mean it's not a company? Otherwise, what separates a subsidiary from just being another team? I assume the difference is t

Does the fact that it's a subsidiary mean it's not a company? Otherwise, what separates a subsidiary from just being another team? I assume the difference is that a subsidiary can be legally considered to be a company on its own altogether, but I'm not a lawyer. If it is though, then assuming companies need a CEO, Zappos still needs one.