The diplomatic corps may, in certain contexts, refer to the collection of accredited heads of mission (ambassadors, high commissioners, and others) who represent their countries in another state or country. As a body, they usually only assemble to attend state functions like a coronation, inauguration, national day or State Opening of Parliament, depending on local custom. They may also assemble in the royal or presidential palace to give their own head of state's New Year greeting to the head of state of the country in which they are based.
The term is sometimes confused with the collective body of diplomats from a particular country—the proper term for which is diplomatic service or foreign service. The diplomatic corps is not always given any formal recognition by its host country, but can be referenced by official orders of precedence.
In many countries, and especially in Africa, the heads and the foreign members of the country offices of major international organizations (United Nations agencies, the European Union, the International Committee of the Red Cross, agencies of the African Union, etc.) are considered members—and granted the rights and privileges—of the diplomatic corps.
Diplomatic personnel in most countries have distinctive license plates, often with the prefix CD, the acronym for the French corps diplomatique.
In many countries the papal nuncio (officially known as the apostolic nuncio) serves as the Dean of the Diplomatic Corps and the corps spokesman on formal occasions. By virtue of Article 4 of the protocol of June 9, 1815 of the Congress of Vienna, the nuncio is dean of the diplomatic corps in the country of appointment. This is generally the case for countries that have Roman Catholicism as the official or main religion.
In practical terms, the Dean of the Diplomatic Corps may have a role to play in negotiating with local authorities regarding the application of aspects of the Vienna Convention and diplomatic immunity, such as the payment of certain fees or taxes, since the receiving country is required "not to discriminate between states." In this sense, the dean has the role of representing the entire diplomatic corps for matters that affect the corps as a whole, although this function is rarely formalized.