The price you pay for an option, called the premium, has two components: intrinsic value and time value. Intrinsic value is the difference between the strike price and the share price, if the stock price is above the strike. Time value is whatever is left, and factors in how volatile the stock is, the time to expiration and interest rates, among other elements. For example, suppose you have a $100 call option while the stock costs $110. Let’s assume the option’s premium is $15. The intrinsic value is $10 ($110 minus $100), while time value is $5.
If in six months the market crashes by 20% (500 points on the index), he or she has made 250 points by being able to sell the index at $2250 when it is trading at $2000—a combined loss of just 10%. In fact, even if the market drops to zero, the loss would only be 10% if this put option is held. Again, purchasing the option will carry a cost (the premium), and if the market doesn’t drop during that period, the maximum loss on the option is just the premium spent.
An option is a contract that allows (but doesn't require) an investor to buy or sell an underlying instrument like a security, ETF or even index at a predetermined price over a certain period of time. Buying and selling options is done on the options market, which trades contracts based on securities. Buying an option that allows you to buy shares at a later time is called a "call option," whereas buying an option that allows you to sell shares at a later time is called a "put option."