Definition of 'Preferred Stock'
A class of ownership in a corporation that has a higher claim on the assets and earnings than common stock. Preferred stock generally has a dividend that must be paid out before dividends to common stockholders and the shares usually do not have voting rights.
The precise details as to the structure of preferred stock is specific to each corporation. However, the best way to think of preferred stock is as a financial instrument that has characteristics of both debt (fixed dividends) and equity (potential appreciation). Also known as "preferred shares".
Investopedia explains 'Preferred Stock'
There are certainly pros and cons when looking at preferred shares. Preferred shareholders have priority over common stockholders on earnings and assets in the event of liquidation and they have a fixed dividend (paid before common stockholders), but investors must weigh these positives against the negatives, including giving up their voting rights and less potential for appreciation.
For more on this interesting hybrid security, read A Primer on Preferred Stocks and Valuation of Preferred Stocks.