In centuries past, Black Friday (from 1610) was school slang for a Friday on which pupils had a big test, and so something to be dreaded. But now it’s attached to the annual discount-shopping frenzy that has been and gone this year. Black Wednesday, when Britain fell out of the European exchange rate mechanism in 1992, was a disaster, and so was Black Monday, the 1987 global stock market crash. Likewise Black Thursday and the following Black Tuesday, bookending the Wall Street crash of 1929. It would be nice to think Black Friday is named in this tradition, to point up the environmental catastrophe of runaway consumerism, but no such luck. It came to denote the beginning of the Christmas shopping season in the 1960s, when “black” referred wryly to city congestion wrought by the shopping hordes.