Generally, a rally will have staying power, technicians say, if, in addition to price movements, it has heavy trading volume and breadth, meaning that several stocks rise for each stock that falls.

Insider trading is hard to prove. To be convicted, a person must have bought or sold a stock based on material information that is both unknown to the general public and likely to have had an important effect on a company's stock price.

It's one of the fundamental principles of the stock market: When interest rates go up, stocks go down. And along with financial companies and cyclicals, technology companies - with their sky-high price-to-earnings multiples - should be among the biggest losers in an environment of rising rates.

Technically a penny stock is any stock trading under five dollars. This is where you find stocks that have the potential to go up hundreds or even thousands of percent.

Big swings in the wholesale price of electricity are not unusual in the summer, when high demand taxes generators' ability to supply power.

It's a trading bounce. These stocks have been dreadful (performers) for several months.