Market capitalization
The total value of a company on the stock market.
Market cap is the share price times the number of shares. It is how companies are ranked from small-cap to mega-cap.
Market capitalization is what the market says a company is worth: the share price times the number of shares outstanding. A stock at 50 dollars with 100 million shares has a 5 billion dollar market cap. It is the standard way to size a company, from small-cap through large-cap to the mega-cap giants.
Cap size is a rough guide to risk and behavior. Large caps tend to be steadier and more liquid; small caps can move faster in both directions and are easier to push around on thin volume. A common mistake is judging a stock as cheap or expensive by its share price alone. A 10 dollar stock is not cheaper than a 500 dollar one; market cap and what the company earns are what tell you the valuation.