After the turkey has been eaten, the football games have been watched and digestion is fully under way, millions of Americans turn to another holiday tradition: planning their Black Friday shopping spree.

That’s right! It’s the day after Thanksgiving, and that means it’s time to shop. Black Friday — the day after Thanksgiving in the United States — signals the beginning of the holiday shopping season.

Although it’s not an official holiday, millions of employers give their employees the day off, and many people use that day to get a jump-start on their holiday shopping. A similar day in Canada and Great Britain is called “Boxing Day.”

Black Friday has become somewhat of a marketing sensation in recent years. Since 2005, it has been the busiest shopping day of the year. To lure shoppers, retailers routinely open their doors as early as 4 a.m. and offer special sales and promotions to the shoppers that arrive early.

Some of the special deals offered by stores are only available in limited quantities. That is why some shoppers intent on getting the best deals often camp out in front of stores overnight so that they’ll be the first in line when the doors open.

But why Black Friday? There are a couple of explanations of how this name came about.

Historians believe the name started in Philadelphia in the mid-1960s. Bus drivers and police used “Black Friday” to describe the heavy traffic that would clog city streets the day after Thanksgiving as shoppers headed to the stores.

Businesses, however, didn’t like the negative tone associated with the Black Friday name. In the early 1980s, a more positive explanation of the name began to circulate.

According to this alternative explanation, Black Friday is the day when retailers finally begin to turn a profit for the year. In accounting terms, operating at a loss (losing money) is called being “in the red” because accountants traditionally used red ink to show negative amounts (losses).

Positive amounts (profits) were usually shown in black ink. Thus, being “in the black” is a good thing because it means stores are operating at a profit (making money).

Regardless of when a retailer turns a profit for the year, it’s clear that Black Friday is a very important day for most retailers. Some retailers are indeed dependent on holiday shopping to turn a profit for the year. For others, it’s a day when they definitely make bigger-than-usual profits — and that’s a lot of black ink!

The recent popularity of Black Friday has spawned another new shopping holiday: Cyber Monday. For those who are too busy to shop on Black Friday — or who just don’t want to fight the crowds — the Monday following Black Friday has become known as Cyber Monday for the many online deals that shoppers can take advantage of from the comfort of their homes.