An envoy is someone a government, or a big organisation, sends to another country as an official representative. They carry a message, they listen, they try to settle something. They speak for the people who sent them.

Though actually, an envoy is not always the ambassador. The ambassador is usually the top diplomat who lives at the embassy. An envoy may go for one job — a talk, a crisis, a special task — and then come home. News writers love special envoy: a person named for climate talks, a war, a broken agreement. That job can be temporary. In older books, envoy can also mean a messenger more widely. It is a formal, politics-and-news word, not a word for a friend you asked to take a note down the street.