I read this at Mental floss:
That's right—in February 1919, just a few months after World War 1 ended, a story appeared in the UK's Manchester Guardian called “World War No. 2.” The Oxford English Dictionary describes it as a "reference to an imagined future war arising out of the social upheaval consequent upon the First World War.” The actual second world war wouldn’t start until 1939.
I think that the writer is mistaken because he says "Oxford English Dictionary describes". I think there should've been "described" instead here. Because the term is not merely a reference. The war has taken place. Additionally the dictionary doesn't include this definition either but it is plausible it might've been there between 1919 and 1939. Am I right?