Price Elasticity of Demand:The measure of how responsive the quantity demanded of a good or service is to a change in its price, calculated as the percentage change in quantity divided by the percentage change in price.
Price Elasticity of Supply:The measure of how responsive the quantity supplied of a good or service is to a change in its price, calculated as the percentage change in quantity supplied divided by the percentage change in price.
Marginal Revenue: The additional revenue a firm earns from selling one more unit of a good or service, calculated as the change in total revenue divided by the change in quantity.