investing traditionally refers to buying a stock or other financial instrument for a long period of time, typically over several years. Assessing good investment opportunities often makes use of fundamental information, such as earnings, but can also use technical analysis to detect long-term trends.
Trading typically refers to buying and selling stocks or other financial instruments for shorter periods of time, typicallly less than a few months. Assessing good trading opportunities typically makes use of trading systems or chart-based techniques to detect short-term patterns.
The main advantage of trading over investing is that it provides the ability to make money regardless of the overall direction of the market or the price of an individual stock.