Please answer a question about the following article about Military history of the United States:

By summer 1918, a million American soldiers, or "doughboys" as they were often called, of the American Expeditionary Forces were in Europe under the command of John J. Pershing, with 25,000 more arriving every week. The failure of Germany's spring offensive exhausted its reserves and they were unable to launch new offensives. The German Navy and home front then revolted and a new German government signed a conditional surrender, the Armistice, ending the war against the western front on November 11, 1918.

What was the official name of the American army that went to fight in Europe in 1918?
American Expeditionary Forces