Elasticity in economics represents the sensitivity of economic parameters like demand, supply, and prices, among others, to changes in affecting factors. It includes price elasticity of demand, which assesses demand changes if prices increase, and income and cross-price elasticity in household theory. Additionally, direct and indirect price elasticity of demand are derived mathematically. Also, firm and market theories apply elasticity to assess the price sensitivity of input demand, production, firm supply, and market representation.