United States Army Rangers

The United States Army Rangers are U.S. Army personnel who have served in any unit which has held the official designation of "Ranger". The term is commonly used to include graduates of the Ranger School, even if they have never served in a "Ranger" unit, because Army regulations and special qualification identifier (SQI) codes provide that the only requirement to earn the "Title: Ranger" is that a soldier "must successfully complete the appropriate training at the Infantry School." In a broader and less formal sense, the term "ranger" has been used, officially and unofficially, in North America since the 17th century, to describe specialized light infantry in small, independent units—usually companies.

Source: Wikipedia — United States Army Rangers (CC BY-SA 4.0)