An ambassador is an official envoy, especially a high-ranking diplomat who represents a state and is usually accredited to another sovereign state or to an international organization as the resident representative of their own government or sovereign or appointed for a special and often temporary diplomatic assignment. The word is also used informally for people who are known, without national appointment, to represent certain professions, activities, and fields of endeavor, such as sales.

A diplomatic mission or foreign mission is a group of people from a state or organization present in another state to represent the sending state or organization officially in the receiving or host state. In practice, the phrase usually denotes an embassy or high commission, which is the main office of a country's diplomatic representatives to another country; it is usually, but not necessarily, based in the receiving state's capital city. Consulates, on the other hand, are smaller diplomatic missions that are normally located in major cities of the receiving state. As well as being a diplomatic mission to the country in which it is situated, an embassy may also be a nonresident permanent mission to one or more other countries.