VIX Index Definition
VIX is the ticker symbol for CBOE Volatility Index. The index, calculated by Chicago Board Options Exchange (CBOE), measures expected volatility of S&P500 stock index in the next 30 days. The exact definition of VIX is: implied volatility of a hypothetical S&P500 option with 30 days to expiration.
VIX Definition in More Detail
For a more detailed explanation, including definitions of the other terms used in the definition above (like ticker symbol, options, or implied volatility), see What is VIX?
The VIX Index is calculated from prices and implied volatility of a broad range of near term options on S&P500. To keep the time period of the implied volatility constant 30 days, options with different time to expiration are weighted accordingly. You can see a more detailed explanation here: VIX Calculation.
Trading the VIX, Options, and Futures
The VIX Index has active derivative markets – VIX options and VIX futures. The index and its derivatives have several specific characteristics with important implications for trading. For more details, including the specifics, possible sources of trading ideas, and how to research and analyze the VIX, see Trading the VIX.