As the clock strikes midnight on New Year's Eve, revelers across the globe will sing "Auld Lang Syne," a song about "old acquaintance be forgot" and, well, other lyrics people may not recall from the New Year's song. 

The song's origins date back to an 18th-century Scottish ballad, with Auld Lang Syne eventually becoming a New Year's celebration staple. Experts explained the song's lyrics, origin and staying power. 

What does "auld lang syne" mean?

Roughly translated, the phrase means "old long since," or "for old time's sake." The song title is actually in Scots language, which is similar to English, according to Scotland's national tourist board.

"'Auld Lang Syne' can be literally translated as 'Old Long Since,' but the literal English does not give a sense of what it means to a user of Scots, where it refers to a shared past underpinning the current relationships of a family, community or professional/social association," Professor Murray Pittock, a literary historian with the Centre for Robert Burns Studies at the University of Glasgow, told CBS News. "As such it is more evocative, nostalgic and communally unifying than any simple English equivalent." 

What are the song's origins?

Today's song comes from a publication by Scottish poet Robert Burns. The poet was trying to preserve Scottish language and culture after Scotland and England formed the United Kingdom, according to Scotland's national tourist board. So he traveled the country and collected old Scots poetry and songs, including "Auld Lang Syne."

"Burns said in one of the letters on view that he listened to an old man singing the song and that it had never been in print or in manuscript until he wrote it down from that old man singing," Christine Nelson, who once curated an exhibition on the song at the Morgan Library in Manhattan, told CBS News in 2012.

The song Burns wrote down can be traced back to "Auld Kyndness Forgot," which was preserved in a manuscript from 1568, Pittock said.

Historians believe that Burns substantially re-wrote the words.

"He didn't make any secret of the fact that he was doing what he called 'mending' these old songs," Nelson said in her 2012 interview. "So that they could be, you know, given to the public for posterity."

His words were first published in 1796, according to the Library of Congress. Burns also sent a slightly revised version to a publisher in 1793, but that version was not published until 1799 — three years after Burns' death. The best known set of words for Auld Lang Syne are the ones published in 1799.

Why do we sing the song every New Year's Eve?

While the song has Scottish roots, its popularity in the U.S. is owed to a Canadian. 

Bandleader Guy Lombardo popularized it after he and his Royal Canadian Big Band played it on a New Year's Eve broadcast in 1929. In 1965, Lombardo told "LIFE" magazine that he came from a part of western Ontario home to a large Scottish population. In that area, it was traditional for bands to end every dance with "Auld Lang Syne."

"The main reason why Lombardo became identified as the Ghost of New Years Past, of New Years Present and of New Years Yet to Come, he says, 'is because Auld Lang Syne is our theme song — and was long before anyone ever heard us on the radio,'" "LIFE" Magazine reported.

After Lombardo's 1929 broadcast, "Auld Lang Syne" went on to become part of popular culture, playing in "Forrest Gump," "Sex and the City" and "When Harry Met Sally."

Harry and Sally even have a conversation about the song, trying to figure out its meaning. 

"My whole life, I don't know what this song means," Harry, played by actor and comedian Billy Crystal, says in the 1989 movie. "I mean, 'should old acquaintance be forgot?' Does that mean that we should forget old acquaintances or does it mean that if we happen to forget them, we should remember them, which is not possible because we already forgot 'em?"

"Well, maybe it just means that we should remember that we forgot them or something," Meg Ryan's character Sally responds. "Anyway, it's about old friends." 

The U.S. Embassy in Italy maybe explained it best in a blog post: "The lyrics of 'Auld Lang Syne' pose the question: How do we best remember the memories, friends and experiences of years before? The answer, Burns tells us, is to 'share a cup of kindness yet' as we journey into the new year." 

In:
• New Year's Eve

Aliza Chasan

Aliza Chasan is a digital producer at 60 Minutes and CBSNews.com. She has previously written for outlets including PIX11 News, The New York Daily News, Inside Edition and DNAinfo. Aliza covers trending news, often focusing on crime and politics.

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