The Encyclopedia Americana (1920)/Pioneers

PIONEERS, in old-time warfare, a detachment of soldiers equipped with pickax, spade, etc., in the proportion of 10 to every battalion of infantry, whose duty it was to clear and repair roads, bridges, etc., as far as possible, for troops on the march. They were placed at the head of the battalion of which they form a part and commanded by a pioneer sergeant. They have long been replaced by the engineer corps. However, the engineers are sometimes termed the “pioneer battalion.”