A permanent representative to the United Nations (sometimes called a "UN ambassador") is the head of a country's diplomatic mission to the United Nations.
Of these, the most high-profile UN permanent representatives are those assigned to headquarters in New York City. However, member states also appoint permanent representatives to the other UN offices in Geneva, Vienna, and Nairobi.
Andrei Andreyevich Gromyko (18 July [O.S. 5 July] 1909 – 2 July 1989) was a Soviet politician and diplomat during the Cold War. He served as Minister of Foreign Affairs (1957–1985) and as Chairman of the Presidium of the Supreme Soviet (1985–1988). Gromyko was responsible for many top decisions on Soviet foreign policy until he retired in 1988. In the 1940s, Western pundits called him Mr. Nyet ("Mr. No"), or Grim Grom, because of his frequent use of the Soviet veto in the United Nations Security Council.
Gromyko's political career started in 1939 in the People's Commissariat for Foreign Affairs (renamed Ministry of Foreign Affairs in 1946). He became the Soviet ambassador to the United States in 1943, leaving that position in 1946 to become the Soviet Permanent Representative to the United Nations in New York. Upon his return to Moscow he became a Deputy Minister of Foreign Affairs and later First Deputy Minister of Foreign Affairs and eventually Foreign Minister. He went on to become the Soviet ambassador to the United Kingdom in 1952.
In diplomatic usage, head of mission (HOM) or chief of mission (COM) from the French "chef de mission diplomatique" (CMD) is the head of a diplomatic representation, such as an ambassador, high commissioner, nuncio, chargé d'affaires, permanent representative, and sometimes to a consul-general. Depending on the context, it may also refer to the heads of certain international organizations' representative offices. Certain other titles or usages that would qualify as a head of mission or equivalent also exist. While they are primarily referred to by the other titles mentioned above, it is common for the diplomatic corps of a country to use deputy head of mission or deputy chief of mission (DCM) as the primary title for the second in command of a diplomatic mission.
In diplomatic missions and foreign services where ambassadors may be political appointees rather than career diplomats, the deputy chief of mission may be the senior career foreign service professional and generally understood to be more than a "deputy."