The term 'Marine, colloquially' is often referred to as a 'LEATHERNECK, ' which is an 11-letter word. The term 'LEATHERNECK' is used to refer to a member of the United States Marine Corps, which is a branch of the United States Armed Forces. The term is derived from the leather stock that was once worn by Marines around their necks in order to keep their heads erect and their uniforms in place. The term has been in use since the 18th century and is still used today to refer to members of the Marine Corps.