A stock is a share in the ownership of a company and represents a claim to the company's earnings and assets. Your return on investment depends on the success or failure of that company.
To learn more, please visit: http://www.finra.org/investors/stock-basics
An ETF, or exchange traded fund, is a security that tracks an index, a commodity, a set of bonds, or a basket of assets. ETFs blend together aspects of mutual funds and conventional stocks. Like mutual funds, ETFs are pooled investment funds that offer investors an interest in professionally managed and diversified portfolios of investments. But unlike mutual funds, ETF shares trade like stocks on stock exchanges and can be bought or sold throughout the trading day at fluctuating prices.
To learn more, please visit: http://www.finra.org/investors/exchange-traded-funds