“Auld Lang Syne” is the song first published in 1796 that is commonly sung at midnight on New Year's Eve in English-speaking countries.
The lyrics are based on a Scots poem by Robert Burns, who wrote them down in 1788 after collecting and adapting older traditional lines. The phrase “auld lang syne” means “old long since,” or more naturally, “for old times' sake.” Its subject is remembrance and friendship rather than a literal countdown.
The tune and words spread widely during the nineteenth and twentieth centuries, helped by printed songbooks and public performances. Guy Lombardo's broadcasts and recordings made the song especially prominent in North American New Year's celebrations.
People often know only the chorus or sing nonstandard versions of the verses. It is also used at farewells, memorial occasions, and other transitions, so it is not exclusively a New Year's song. “Auld Lang Syne” is a Scots title, not the name of a place or a person.