The contract is an agreement, or promise, for the buyer to purchase oil
at a
certain price in the
future (the spot
price)
at a
certain date in the
future (the contract's maturity) from the seller.
While it's possible to invest directly
in commodities (say, by buying 10,000 pounds of sugar), most commodities are traded through «
futures contracts» — a promise to buy or sell a
certain amount of the commodity
at a specified
price on a
certain date.