·add. ·- In the United States army, the Corps of Engineers, a corps of officers and enlisted men consisting of one band and three battalions of engineers commanded by a brigadier general, whose title is Chief of Engineers. It has charge of the construction of fortifications for land and seacoast defense, the improvement of rivers and harbors, the construction of lighthouses, ·etc., and, in time of war, supervises the engineering operations of the armies in the field.