The total market value of a firm. It is defined as the product of the company's stock price per share and the total number of shares outstanding. In the case of a newly public company, the total shares outstanding can greatly exceed the float, due to lock-up agreements. Companies often pay their employees with stock options, so buy side analysts look at the fully-diluted share count to calculate market cap.
An investment style that emphasizes buying stocks with the strongest price appreciation trend or shorting stocks with the strongest price depreciation trend. Momentum investors are often unconcerned with company fundamentals and focus instead on near term event-driven catalysts likely to drive prices strongly up or down.