Quantity Demanded:The amount of a good or service that consumers are willing and able to purchase at a given price during a specific period of time.
Law of Demand:The principle that, all else equal, as the price of a good or service rises, the quantity demanded falls, and as the price falls, the quantity demanded rises.
Elasticity of Demand: A measure of the responsiveness of the quantity demanded to a change in the price of a good or service, calculated as the percentage change in quantity demanded divided by the percentage change in price.