The specified price on an option contract at which the contract may be exercised, whereby a call option buyer can buy the underlier or a put option buyer can sell the underlier. The buyer's profit from exercising the option is the amount by which the strike price exceeds the spot price (in the case of a put), or the amount by which the spot price exceeds the strike price (in the case of a call). In general, the smaller the difference between spot and strike price, the higher the option premium. also called exercise price.