Demand is defined as a schedule of the quantities fo good that will be purchased at various prices similarly the supply refers to the schedule of the quantities of a good that will be offered for sale at various prices. To be more correct supply of commodity is the schedule of the quantities of a commodity that would be offered for sale at all possible price during a period of time for example a day a week a month and so on.

Supply should be carefully distinguished from stock is the total volume of a commodity which can be brought into the market for sale at a short notice and supply means the quantity which is actually brought in the market. For perishable commodities like fish and fruits supply’ and stock are the same because whatever is in stock must be disposed of. The commodities which are no perishable can be held back if prices are not favorable. If the price is high larger quantities of non-perishable commodities are offered by the sellers from their stock. And if the price is low only small quantities are brought out for sale in short stock is potential supply.