What was the original meaning of the term "Black Friday" before it became associated with post-Thanksgiving shopping?

Black Friday has become a global shopping phenomenon, marking the unofficial start of the holiday shopping season. But how much do you really know about its origins? Test your knowledge about this massive retail event that transformed from a local Philadelphia term to a worldwide shopping festival generating billions in sales. This question explores the surprising historical roots of a day that has shoppers camping outside stores and crashing websites in pursuit of deals.

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A stock market crash in 1929 that occurred on a Friday
A term used by Philadelphia police in the 1950s to describe traffic chaos when shoppers and tourists flooded the city after Thanksgiving
The day retail stores traditionally went from operating at a loss ('in the red') to making a profit ('in the black') for the year
A marketing campaign created by department stores in the 1970s to promote post-Thanksgiving sales