United States Marines is a term that refers to the military branch of the United States Armed Forces that specializes in amphibious operations, ship-to-shore assaults and rapid deployment. Additionally, there are several synonyms for United States Marines, such as Marine Corps, Marine Corps Reserve, US Marines, and Leathernecks. The term "Leatherneck" comes from the leather collar worn by Marines during the 18th and 19th centuries to protect their necks from sword slashes. The term "Devil Dogs" is another nickname for the Marines, awarded by the Germans during World War I. The term "Jarhead" is another term for the Marines that originated from the close-cropped haircuts they were given while in boot camp.