We're seeing an incredibly diverse set of international conflicts, with just this morning saying combat troops from Russia entering Ukrane, US bombing syria, etc. Some have called this the start of WWIII, though I don't know enough to make that call.

In the current events leading up to WWI, obviously no one called it "world war" - my understanding that at the time and shortly after people called it "The Great War". And then in the initiation of the conflict of what we now called WWII, surely no one was calling a "world war" either.

So when did I and II get linked, and they both get called World War? Was it during WWII, or after? Was it a specific text or article that called them out that way?

Thank you.