An accredited diplomat sent by a country as its official representative to a foreign country
the American ambassador
The cuckoo, Cuculus canorus.
A person serving (usually unofficially) to promote goodwill between countries, institutions, etc.; now chiefly (frequently with capital initials) a well-known person (especially a celebrity) appointed by a charity or other organization to publicize its activities or promote a specified cause.
An ambassador with special duties, not appointed to a particular country
A diplomat sent by one state or monarch on a diplomatic mission to another
An ambassador with full powers to sign treaties or otherwise act for the state or monarch