In financial markets, stock is the capital that a firm gets by giving out and distributing of shares.
A person or organization which holds shares of stocks is called a shareholder. The whole value of the stocks that a firm has issued is called its market capitalization.
Stocks can be bought and sold from the stock exchange. Someone who buys and sells stock is called a stockbroker.
In the United Kingdom and Australia, the term share is used the same way as stock is described in the United States.