WHAT IS BLACK FRIDAY?

The day following Thanksgiving—commonly referred to as Black Friday—has become one of the busiest shopping days of the year in the United States. National chain stores traditionally offer limited money-saving specials on a wide variety of goods in an effort to lure shoppers into stores while offering similar deals online.

It is believed by many that the term Black Friday derives from the concept that businesses operate at a financial loss, or are “in the red,” until the day after Thanksgiving, when massive sales finally allow them to turn a profit, or put them “in the black.” However, this is untrue. 

A more accurate explanation of the term dates back to the early 1960s, when police officers in Philadelphia began using the phrase “Black Friday” to describe the chaos that resulted when large numbers of suburban tourists came into the city to begin their holiday shopping and, in some years, attend Saturday’s annual Army-Navy football game. The huge crowds created a headache for the police, who worked longer shifts than usual as they dealt with traffic jams, accidents, shoplifting, and other issues.

source: https://www.britannica.com/story/why-is-it-called-black-friday