"Doughboys" was a nickname for American soldiers during World War I. The origins of the term are unclear, but appear to date back to Mexican-American War (1846-1848). Another theory claims that it began during the Civil War due to the dumpling shaped buttons worn by Union soldiers. Initially the term only referred to the infantry, however during World War I it was expanded to cover all American forces in France. The term lost favor after the war and was replaced in common usage by "G.I."