Black Friday, infamous for its flashy advertisements, major discounts and deal-driven mall brawls, has grown into a mainstay shopping holiday – but how did the sales bonanza get its name?

You may have heard that the name is a reference to a welcome boom in sales for retailers, who go from operating at a loss, or “in the red,” to earning a profit “in the black” the day after Thanksgiving as shoppers flood stores to pounce on once-in-a-year discounts.

But that story is at least partly a myth that obscures a somewhat darker episode in the history of holiday shopping, according to Encyclopaedia Britannica and historians.

In the 1960s, Philadelphia police officers used the phrase to describe the chaos that ensued the day after Thanksgiving, when crowds of shoppers from nearby suburbs and tourists swarmed the city ahead of its annual Army-Navy football game held on Saturday.

The city’s cops were not allowed to request off and had to work extra-long shifts to deal with the endless throngs of visitors. 

Some took advantage of the holiday rush and pocketed store merchandise, turning it into a notorious shoplifting day — and a huge headache for police officers.

The cops’ term “Black Friday” caught on like wildfire throughout the city, and Philadelphia retailers moved quickly to try to squash it – promoting the shopping rampage as “Big Friday” – but it didn’t stick.

By the late 1980s, retailers had managed to rebrand the shoplifting nightmare — pitching it as a major sale using the “red to black” profit explanation.

Since then, the phrase has stuck and Black Friday has grown into a major shopping holiday. Other major sale days, like Cyber Monday and Small Business Saturday, have cropped up along the way.

Major retailers like Amazon and Target have created their own e-commerce and brick-and-mortar discount weeks in October to try to catch their last big bout of sales before Thanksgiving weekend.