a group of high-ranking military officers who represent the Navy, Army, Air Force and Marines. They assist the civilian leaders of the Department of Defense in integrating policies and programs, and advise the President and National Security Council when asked. The Joint Chiefs of Staff is headed by a Chairman.
The Joint Chiefs of Staff (JCS) is a group comprising the Chiefs of service of each major branch of the armed services in the United States armed forces. Similar organizations, sometimes known as Chiefs of Staff Committees (COSCs) in the Commonwealth of Nations, are common in other countries.