Doughboy is an outdated slang term for a United States Army infantryman, best known from its use in World War I, although it dates back to the Mexican-American War of 1846-48.
The origin of the term is unclear. The most often cited explanation is that it arose during the Mexican-American War, after observers noticed U.S. infantry forces were constantly covered with chalky dust from marching through the dry terrain of northern Mexico, giving the men the appearance of unbaked dough. Another suggestion is that doughboys were so named because of their method of cooking field rations of the 1840s and 1850s, usually doughy flour and rice concoctions baked in the ashes of a camp fire, although this does not explain why only infantryman received the appellation. Still another explanation involves pipe clay, a substance with the appearance of dough, used by pre-Civil War soldiers to clean their white garrison belts. None of these theories are provable.
