World War IWorld War I
the war (1914-18) between the Allies (Great Britain, France, Russia, the U.S., Italy, Japan, etc.) and the Central Powers (Germany, Austria-Hungary, etc.)
World War I
A war fought from 1914 to 1918, in which Great Britain, France, Russia, Belgium, Italy, Japan, the United States, and other allies defeated Germany, Austria-Hungary, Turkey, and Bulgaria.