Black Friday is the discount shopping day that follows American Thanksgiving, which is always on a Thursday. Retailers promote Black Friday as the day to start shopping for Christmas. Black Friday is often advertised with "Christmas Sales" as well as "Thanksgiving Sales."

The word "black" in Black Friday refers to the term "in the black" meaning making a profit. Today, Black Friday is not a crucial source of profit to retailers, but is important in driving traffic into stores. Many retailers mail special Black Friday circulars to consumers, announcing deeply discounted items in the hopes that consumers will visit their store on Black Friday.

Marketing studies have shown that many Black Friday shoppers will buy other merchandise from stores in which they planned to visit to purchase advertised items. The increased volume of shoppers buying non-discounted items makes Black Friday profitable for retailers even though they do not make much profit on deeply discounted merchandise.

While some people head out on a Black Friday to just "window shop", others insist they will not shop on a Black Friday at all, citing overcrowded parking lots and wall-to-wall shoppers as reasons to forgo saving money at sales. Yet many others not only pre-plan which items they will buy from which stores, they are willing to brave long lines to get bargains on items they want. Each year, Black Friday has so many interested shoppers participating that it remains a retailing tradition in the United States.

Electronics and toys are popular Christmas gifts and are often the most sought-after bargains during Black Friday shopping excursions. Retailers often slash prices on the latest electronics and toys by as much as half or even one third of their suggested retail price. Retailers know consumers will respond to such enormous opportunities to save on Christmas shopping costs. Jewelry is another popular Black Friday item that shoppers look for discounts on, although gigantic discounts on jewelry items are not usually as common as drastically slashed prices on toys and electronics are.

As supplies on deeply discounted goods are often limited by retailers, "doorbuster" sales are common on a Black Friday. The people who arrive early to line up closest to the store's front doors are the only ones sure to be able to purchase the advertised bargains if the store runs out. To help compensate for this, most stores try to have as many of each item as possible and/or mention the number available on their circular. Some stores also give out incentive prizes to those in line such as gift cards good for free merchandise in the store to the first hundred or more shoppers.