Esprit De Corps: The term is French, and it literally means "The Spirit Of The Body," Originally it was used to describe the morale of military troops.
In Marine Corps boot-camp, drill instructors wear different colored duty belts based on their position, making their role easily identified even from a distance, such as from across the drill field. Hence Gunnery Sergeant Carter (Frank Sutton) wears a black duty belt indicating he is the Senior Drill Instructor. Corporal Johnson (Jerry Dexter) wears the olive green webbed duty belt as a junior drill Instructor.