Note that neither of the world wars were referred to as such by anyone, even colloquially, until the fireworks really got going. And the beginning phases of both share some unsettling parallels with our current situation in a variety of ways.
How successfully or unsuccessfully the rest of the world is able to handle Russian (and, as a potential follow-on in the coming years, Chinese) expansionism and aggression may determine whether or not this ends up being “the Ukrainian War” or “the early phases of World War III” in textbooks written decades from now.