"Auld Lang Syne" (Scots pronunciation: [ˈɔːl(d) lɑŋ ˈsəi̯n]) is a Scottish song. In the English-speaking world, it is traditionally sung to bid farewell to the old year at the stroke of midnight on New Year's Eve/Hogmanay. By extension, it is also often heard at funerals, graduations, and as a farewell or ending to other occasions; for instance, many branches of the Scouting movement use it to close jamborees and other functions. The text is a Scots-language poem written by Robert Burns in 1788 but based on an older Scottish folk song.
https://en.wikipedia.org/wiki/Auld_Lang_Syne