Definition: The Secretary of State (the position is more commonly called "Foreign Minister" in other countries) is the highest ranking, non-elected person in the U.S. government. He or she sits fourth in the order of presidential succession after the Vice President, Speaker of the House, and President pro tempore of the Senate. The first Secretary of State was Thomas Jefferson.
The secretary runs the U.S. State Department, serves in the presidential cabinet, and is the principal advisor to the president on U.S. foreign policy. The State Department maintains this list of past secretaries.