What is the origin and context of use of 'au revoir'?

The phrase "au revoir" originates from French and translates directly to "until we meet again" or "goodbye" in English. It's a commonly used parting phrase in French-speaking countries and is also widely recognized and used in English-speaking contexts. The context of using "au revoir" is typically more formal or polite compared to casual farewells, but not as formal as "adieu".