What came up with elasticity?

Elasticity, in economic terms, refers to the responsiveness of one variable to changes in another variable, typically used to measure how the quantity demanded or supplied of a good responds to changes in price. The concept was developed in the 19th century, with significant contributions from economists like Alfred Marshall, who formalized the concept in his work on supply and demand. Elasticity can be categorized into different types, such as price elasticity of demand, income elasticity, and cross-price elasticity, each providing insights into consumer behavior and market dynamics.