Option

(1) An instrument that gives the owner the right to buy or sell a specified number of shares of a specified stock at a specified price within a specified period of time. A call option allows the buyer to purchase the underlying stock at any time up to the expiration date of the contract. A put option allows the buyer to sell the underlying stock at any time up to the expiration date of the contract.  (2) A contract that gives the buyer the right, but not the obligation, to buy or sell a specified quantity of a commodity or other instrument at a specific price within a specified period of time, regardless of the market price of that instrument. Refer to Put and Call.