When did people begin calling the war between 1939 and 1945 "World War II"?

by DerekZoolanderJr

I know that in the years between WWI and WWII, people called WWI "The Great War." However, what did people call WWII during and immediately after the war? When did people start calling it WWII and who coined the names for WWI and WWII?

davepx

Time, 12 June 1939.

Roosevelt used "Second World War" on 8 March 1941.