Is it ensure, insure, or assure?
late 14c., from Old French futur, from Latin futurus "going to be, yet to be," as a noun, "the future," irregular suppletive future participle of esse "to be," from PIE *bheue- (see be). The English noun (late 14c.) is modeled on Latin futura, neuter plural of futurus.
A contract to buy or sell a specified amount of a commodity or financial instrument at an agreed price at a set date in the future. If the price for the commodity or financial instrument rises between the contract date and the future date, the investor will make money; if it declines, the investor will lose money. The term also refers to the market for such contracts.