This part applies to the Office of the Secretary of Defense, and the Military Departments; the Chairman of the Joint Chiefs or Staff; and the Defense Agencies referred to collectively in this part as the ``DoD Components''). The term ``Military Departments,'' as used in this part, refers to the Departments of the Army, the Navy, and the Air Force. The term ``Secretary concerned'' refers to the Secretaries of the Military Departments. The term ``Military Services'' refers to the Army, the Navy, the Air Force, the Marine Corps. The term ``Reserve components'' refers to the Army Reserve, Army National Guard of the United States, Air Force Reserve, Air National Guard of the United States, Naval Reserve, Marine Corps Reserve.