The forward curve (or "Forward Curve") is the representation of the various maturities of a contract or a commodity. The forward curve of wheat Matif example, consists of all wheat futures, which are currently listed on the Matif. On the x axis is the time indicated on the y axis of the unit price.
Where prices for the maturities in the further future over the next due date, is called contango. Take the case of a long maturities from, it is called backwardation.