Macho Money Definitions - What Is A Market Index?
What is a “market index?" According the SEC, a market index tracks the performance of a specific "basket" of stocks considered to represent a particular market or sector of the world stock market or the economy.
There are indices for almost every conceivable sector of the economy and stock market.
USAA Certified Financial Planner, Scott Halliwell, does a great job in this video of giving a more thorough explanation of a market index with some examples.