http://blog.christianmoney.com/2010/06/invest-in-spiders-spdrs-to-cash-in-on-new-opportunities.html

An exchange-traded fund (or ETF) (also known as Exchange-Traded Product (ETP)) is an investment fund traded on stock exchanges, much like stocks. An ETF holds assets such as stocks or bonds and trades at approximately the same price as the net asset value of its underlying assets over the course of the trading day. Because of their low costs, tax efficiency, and stock-like features.

James L. Paris http://ChristianMoney.com