A legally binding agreement to buy or sell a commodity or financial instrument in a designated future month at a price agreed upon today by the buyer and seller. Futures contracts are standardized according to the quality, quantity, and delivery time and location for each commodity. A futures contract differs from an option because an option is the right to buy or sell, while a futures contract is the promise to actually make a transaction. A future is part of a class of securities called derivatives, so named because such securities derive their value from the worth of an underlying investment.