A production possibility curve (PPC) is a curve which shows various combinations of the amounts of two goods which can be produced within the given resources. It shows that, as a firm produces more of a particular good, less of the other combination would be produced.
For instance, if two different products say X and Y are meant to be produced from a particular raw material, if the producer produces more of commodity X from the available material, the materials used in the production of commodity Y would be less. The producer can decide to produce equal amount of each product, but if more of one is produced, less of the other product would be produced.