ambassador

Highest ranking diplomatic representative of one sovereign state to another. He or she is the chief officer of an embassy which is normally located in the capital of the country. The person chosen as an ambassador must be acceptable to the host country and may be declared 'persona non grata' before or after taking up the office. Diplomatic immunity and personal safety of the ambassador (and that of his or her staff) are formally guaranteed throughout the world since the 1815 congress of Vienna and were amplified by the 1961 Vienna Convention On Diplomatic Relations. See also high commissioner.