Demand:The desire for a commodity of an individual or a group will be called their demand when they are able to pay for that commodity. That is demand is desire with account to pay.
In Benham’s words,
“Demand for anything at a given price is the amount of it which will be bought per unit of time at that price.”
Another definition of demand is ―
“By demand we mean the various quantities of a given commodity or service which the consumers would buy in a market in a given period of time at various prices or at various incomes or at various prices of related goods.”