
Originally Posted by
artjomh
September 1, 1939 to September 2, 1945 is more of a traditional textbook dating rather than a period that fits any concrete definition of a "world war".
You can easily separate the constituent components of WW2 (Second Sino-Japanese War, Winter War, Soviet-Japanese border conflict, Phoney War, Continuation War, Great Patriotic War, Pacific Theater of Operations) and say that these are all separate wars, just like the France and Co. vs the World adventures I described earlier.
It's a matter of perspective and, I guess, traditional historiography.