Entitled: Artillery vehicles - Camouflaging Department, American Car & Foundry Company, Detroit, Michigan. Showing women employees in ordnance plant during the first World War. U.S. Army Signal Corps photo circa 1914/18. During WWI, women started working jobs that were traditionally filled by men. These jobs included police officer, bank clerk, ticket seller, elevator operator, chauffeur, street car conductor, railroad trackwalker, section hand, locomotive wiper and oiler, locomotive dispatcher, block operator, draw bridge attendant, and employment in machine shops, steel mills, powder and ammunition factories, airplane works, boot blacking and farming. The French slang word camouflage came into common English usage during WWI when the concept of visual deception developed into an essential part of modern military tactics. In that war, long-range artillery and observation from the air combined to expand the field of fire, and camouflage was widely used to decrease the danger of being targeted or to enable surprise.