noun
doyen of the diplomatic corps; head of a diplomatic mission
Formal term for the most senior diplomat in a country, often the ambassador with the longest tenure. Used in diplomatic contexts.
彼は日本における主席外交官として、各国の大使と会談した。
As the doyen of the diplomatic corps in Japan, he met with ambassadors from various countries.
主席外交官の役割は、外交団の代表として儀礼的な行事に参加することだ。
The role of the doyen is to participate in ceremonial events as the representative of the diplomatic corps.