Synonyms for First World War (same or very similar meaning)
WordNet sense 1 (a war between the allies (Russia, France, British Empire, Italy, United States, Japan, Rumania, Serbia, Belgium, Greece, Portugal, Montenegro) and the central powers (Germany, Austria-Hungary, Turkey, Bulgaria) from 1914 to 1918):
World War I, Great War, War to End War, World War 1From the ODE community, based on WordNetadd/edit