According to Business Insider, there’s no clear origin of the term “Black Friday.” The most popular explanation is that the revenues generated from the day’s sales are so great, they can push retailers “into the black” for the year. But the earliest reference found to that explanation is 1981, which is many years later than the name became popular. In 1994, a Philadelphia Inquirer reporter claimed he popularized the term by using it after the Philadelphia police started using it in the 1960s.