Demand
The supply of willing and able buyers in the marketplace or lack thereof.
Demand is an economic concept that relates to a consumer's desire to purchase goods and services and willingness to pay a specific price for them. An increase in the price of a good or service tends to decrease the quantity demanded. Likewise, a decrease in the price of a good or service will increase the quantity demanded.
Demand is a concept that consumers and businesses are very familiar with because it makes sense and occurs naturally in the course of practically any day. For example, shoppers with an eye on products that they want will buy more when the products' prices are low. When something happens to raise the prices, such as a change of season, shoppers buy fewer or perhaps none at all.
Generally speaking, there is market demand and aggregate demand. Market demand is the total quantity demanded by all consumers in a market for a given good. Aggregate demand is the total demand for all goods and services in an economy. Multiple stocking strategies are often required to handle demand.