That is a good question! Tbh, I'm not sure about what other English-speaking countries called WW1. I did some quick research on Australian terms for the WW1 just now. It looks like it's known as "WW1" or "the Great War", but I couldn't find any details on when they used which terms.
I know that in Chinese literature, before WW2, they called the former world war "World War" (世界大戰) or "the European War" (歐戰) since the war primarily took place in Europe. So, you have me there :) If you time traveled back to China during 1910's you would probably need to clarify :)