The answer to the crossword puzzle is 'NATL', which stands for the National Department of Defense. The Department of Defense is a federal executive department of the United States government responsible for coordinating and supervising all agencies and functions of the government concerned directly with national security and the United States Armed Forces. It is the largest employer in the world, with over 3 million employees. The Department of Defense is headed by the Secretary of Defense, who is a member of the Cabinet of the President of the United States.