The stock market is a term we use everyday that means that  stocks and bonds are traded "bought and sold". The whole idea is to but a stock or bond hold on to it for a while then sell it for more than you  bought it for. A stock is a shared owner ship in a company. So a business like McDonald's is truly owned by many people. So, when you sell a stock your selling your part ownership of that company. A bond is like a loan a person gives you money and you have to pay it off in a certain amount of years, days, monthes, depending on how big the loan is. But they add interest which is the money they add on for the loan.