The major U.S. shopping day held on the Friday after Thanksgiving is Black Friday.
The term became widely associated with the start of the Christmas shopping season in the United States. Retailers traditionally offered substantial discounts, and many stores opened early to attract customers. In the late 20th and early 21st centuries, the event expanded from one day into a longer promotional period.
Philadelphia police officers helped popularize the expression in the 1950s and 1960s. They used it to describe the heavy traffic and crowds that followed Thanksgiving, particularly when shoppers and visitors arrived before the Army–Navy football game.
The phrase is sometimes explained through the accounting idea of moving from losses into profit, or “the black,” but that interpretation developed later. Cyber Monday is a separate online-focused shopping event held after the weekend.