Definition of 'Index Futures'
A futures contract on a stock or financial index. For each index there may be a different multiple for determining the price of the futures contract.
Investopedia explains 'Index Futures'
For example, the S&P 500 Index is one of the most widely traded index futures contracts in the U.S. Stock portfolio managers who want to hedge risk over a certain period of time often use S&P 500 futures to do so. By shorting these contracts, stock portfolio managers can protect themselves from the downside price risk of the broader market. However, by using this hedging strategy, if perfectly done, the manager's portfolio will not participate in any gains on the index; instead, the portfolio will lock in gains equivalent to the risk-free rate of interest.
Alternatively, stock portfolio managers can use index futures to increase their exposure to movements in a particular index, essentially leveraging their portfolios.