Black Friday is the Friday following Thanksgiving Day in the United States．It has been regarded as 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．Tolure shoppers，retailers （零售商）routinely open their doors as early as 4a．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？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 block 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 （会计行业），operating at a loss is called being"in the red"because accountants traditionally used red ink to show negative amounts．Positive amounts were usually shown in black ink．Thus，being"in the black"is a good thing because it means stores are operating at a profit．

Recently，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 Mond