By John McCrank NEW YORK (Reuters) – The sudden drop in European shares on Monday following an erroneous trade in the Nordic markets is the latest example of a “flash crash” in which the price of an asset quickly drops before bouncing back. The term “flash crash” became part of the market’s lingo after the Dow Jones Industrial Average cratered around 1,000 points in May 2010, wiping out nearly $1 trillion in shareholder value before mostly rebounding in a matter of minutes. Flash crashes are examples of extreme market volatility or structural problems and they can erode investor confidence. Mo…