Do you know how "Black Friday" was named?

The day's name originated in Philadelphia, where it originally was used to describe the heavy and disruptive pedestrian and vehicle traffic which would occur on the day after Thanksgiving. Use of the term started before 1961 and began to see broader use outside Philadelphia around 1975. Later an alternative explanation was made: that retailers traditionally operated at a financial loss from January through November, and "Black Friday" indicates the point at which retailers begin to turn a profit, or "in the black".