Stocks represent partial ownership in a company. When you purchase stocks, you become a partial owner of the business and are entitled to vote and receive dividends. There are two main types of stock markets - the primary market where companies first issue stock, and the secondary market where existing stocks are traded. Stock prices fluctuate based on supply and demand, and various company and market factors can influence prices. Investing in stocks provides an opportunity for high returns but also carries high risks since prices can fall significantly.