Two emails:

Dear Jonah:
From what I’ve read in pre-World War II books, the 1914-1918 conflict was generally referred to as “the World War.”
Now what follows is a pet theory of mine, confirmed by no particular research. But I’m more or less convinced that the terms “World War I” and “World War II” began as Time-isms. That is, terms coined by Time Magazine when that particular magazine was fairly obnoxious about coining cutesie terms and streamlining journalistic prose. We don’t realize it now because the terms are so familiar, but “World War I” and “World War II” are a bit odd and artificial-sounding, the creation of someone too clever by half, but just right for Time in that era.
What makes me think this is that some years ago, while researching published articles on Superman (of all things), I came across a Time article printed just after the German invasion of Poland, light-heartedly discussing the dilemma faced by the creators of an all-powerful fictional character in the light of real-world events. (That is, if he really existed, Superman could easily put a stop to the European war. So how do the strip’s creators explain why he doesn’t?) This was published in late ‘39, about as early as possible after the war broke out, and yet the article used the term “World War II.” I don’t know if the term was in use before that (as it might well have been, since the concept of a second world war looming in the near future was not unfamiliar in the late ’30s), but it’s amusing to think that the first use of “World War II” ever might have been in an article about Superman.
“World War Eye” was used in some time travel novel I once read. The heroine, a girl from the 1890s, is briefly brought forward to the present day, and while looking around the hero’s apartment, asks about the title of some book on his shelves, “What’s World War Eye?” The hero just feels dismay that he’ll have to tell her what’s going to happen to in the Twentieth Century…

And:

Don’t let that correspondent diffuse any righteously pedantic outrage. Doesn’t it always bother you that Star Trek races tended name their planet in reference to orbit number of their star, like “Legara IV” from TNG and “Camus II” from TOS? As if Earth is “Sol III.” Unbelievable.