Kepi - flat circular cap with a visor

"The kepi is a cap with a flat circular top and a peak, or visor. In English, the term is a loanword of French: képi, itself a re-spelled version of the Alemannic German: Käppi, a diminutive form of Kappe, meaning "cap". In Europe, this headgear is most commonly associated with French military and police uniforms, though versions of it were widely worn by other armies during the late 19th and early 20th centuries. In North America, it is usually associated with the American Civil War, as it was worn by soldiers on both sides of the conflict. - Wikipedia"