Black Friday is the day millions of Americans and Canadians brave long lines and possible physical injury to score shopping deals. But where did Black Friday come from and where did it get its name?

The term "Black Friday" made its first appearance in the U.S. in 1869. At the time, the term had nothing to do with shopping, and was used on Sept.  24 when the . As for the shopping tradition, there are several theories floating around.

The accounting theory

One theory is that after a year of operating at a loss, stores started after Thanksgiving, seen as the traditional start to the Christmas holiday season. In accounting terms, these companies went from being in the red (losses) to the black (profits).

The traffic theory

Another theory comes from Philadelphia, where police officers used the term "Black Friday" for the first time in the 1960s to describe the traffic and congestion following Thanksgiving. The term was also used to describe the crowds arriving on the Friday ahead of the popular Army-Navy college football game.

The term 鈥淏lack Friday鈥 was then changed to 鈥淏ig Friday鈥 in a bid to remove the sombre connotations. The plan obviously didn鈥檛 succeed.

After being used in Philadelphia for a few of years, the term then appeared in a . The expression later spread throughout the U.S.

What about Canada?

Canadian Black Friday sales started in the early 2000s, when the Canadian and U.S. dollar were almost equivalent.

This encouraged Canadian stores to offer big discounts to keep shoppers north of the border. Online sales have also boosted Canadians' interest in Black Friday.

According to the Retail Council of Canada鈥檚 , the Black Friday weekend has now eclipsed Boxing Day as the best time to get deals. Forty per cent of the 2,504 Canadians who answered the survey plan to take advantage of deals on Black Friday this year. Fifty per cent of them will be shopping online, on their computer, tablet or mobile device.