What's the meaning of Price elasticity ≠ slope of the demand curve？

Price elasticity and slope of the demand curve are two different concepts that are often confused with each other. Price elasticity refers to the degree of responsiveness of the quantity demanded of a product to a change in its price, while the slope of the demand curve refers to the rate at which the quantity demanded of a product changes with respect to a change in its price.

Price elasticity is measured by the percentage change in quantity demanded divided by the percentage change in price, while the slope of the demand curve is measured by the change in quantity demanded divided by the change in price. Therefore, even though both concepts are related to the relationship between price and quantity demanded, they are not the same thing and cannot be used interchangeably.