noun, noun which may take the genitive case particle 'no'
Refers to a diplomatic ambassador representing a country. Can also be used attributively with の to modify other nouns (e.g., 大使館 'embassy').
彼は日本大使としてフランスに赴任した。
He was posted to France as the Japanese ambassador.
大使館でビザを申請
I applied for a visa at the embassy.