The Sturmabteilung or SA (German for "Storm division", usually translated as "stormtroop(er)s"), functioned as a paramilitary organization of the NSDAP — the German Nazi party. It played a key role in Adolf Hitler's rise to power in the 1930s.
SA men were often called "brownshirts", for the color of their uniforms, and to distinguish them from the SS, who wore black and brown uniforms (compare the Italian blackshirts). Brown-colored shirts were chosen as the SA uniform because a large batch of them was cheaply available after World War I, having originally been ordered for German troops serving in Africa.
The SA was also the first Nazi paramilitary group to develop pseudo-military titles for bestowal upon its members. The SA ranks would be adopted by several other Nazi Party groups, chief among them the SS. They were very important to Hitler's rise to power until they were completely replaced by the SS.