It's not conclusive, but all signs point to the term "Black Friday" originating in Philadelphia.
And it had nothing to do with retailers going into the black in their ledger books.
Numerous accounts point to the term originating within the Philadelphia Police Department in the late 1950s or early 1960.
In those days, the Friday after Thanksgiving not only marked the start of the Christmas Holiday shopping season, but it also was the day before the Army-Navy Game, a Philadelphia fixture.
That meant traffic. Lots of it.
In a report to the American Dialect Society, Bonnie Taylor-Blake cites a 1961 article in Public Relations News on post-Thanksgiving Day shopping as making the Philadelphia connection.
"The resulting traffic jams are an irksome problem to the police and, in Philadelphia, it became customary for officers to refer to the post-Thanksgiving days as Black Friday and Black Saturday," the article said, according to Taylor Black.
Others have cited Philadelphia stamp dealer Earl Apfelbaum for using the term in a column for a philatelic publication in January 1966.
Reporting on the busy day his shop had on Nov. 26, 1965, Apfelbaum also noted that Philadelphia police called the day "Black Friday."
"It is not a term of endearment to them," he wrote, according to Examiner.com. "'Black Friday' officially opens the Christmas shopping season in Center City, and it usually brings massive traffic jams and overcrowded sidewalks as the downtown stores are mobbed from opening to closing."
Until then, "Black Friday" usually referred to the stock market crash of 1869.
Retailers, for obvious reasons, did not like the term, although their employees, on the front line of the onslaught of shoppers, embraced the original meaning.
Some oral accounts hold that Peter Strawbridge, president of Strawbridge & Clothier, gave "Black Friday" its currently accepted meaning as the day retailers went from the red into the black. But no documentation has yet been found to support that.
But he did say this to the Inquirer in 1984: "It sounds like the end of the world, and we really like the day. If anything it should be called 'Green Friday.'"
The term, while common in the Philadelphia area in the 1970s, did not become a national phenomenon until the late 1980s or early 1990s.
As a 1985 Inquirer story noted, retailers in Cincinnati and Los Angeles were still unaware of the term at that tome.
Somewhere along the way, it became an unofficial national holiday and an event for news organizations to play up on what is usually slow news day.