Black Friday (also called Blitz Day), the day after Thanksgiving in the United States, is historically one of the busiest retail shopping days of the year. Many consider it the "official" beginning to the Christmas shopping season. The "black" in the name comes from the standard accounting practice of using red ink to denote negative values (i.e., losses) and black ink to denote positive values (profits). Black Friday is the day when retailers traditionally get back "in the black" after operating "in the red" for the previous months. The term may also be used by retail employees to express their antipathy towards it, as an analogy to Black Thursday as a day of general chaos.

Although Black Friday is typically the busiest shopping day of the year in terms of customer traffic, it is not typically the day with the highest sales volume. That is usually either the last Saturday before Christmas or December 23.

To some social activists, this day was deliberately chosen as Buy Nothing Day to protest the rampant consumerism that they say seems most prevalent on that day.