Elasticity (physics)

Continuum mechanics
Laws Conservations Energy Mass Momentum Inequalities Clausius–Duhem (entropy)
Solid mechanics Stress Deformation Compatibility Finite strain Infinitesimal strain Elasticity (linear) Plasticity Bending Hooke's law Material failure theory Fracture mechanics Contact mechanics (frictional)
Fluid mechanics Fluids Statics · Dynamics Archimedes' principle · Bernoulli's principle Navier–Stokes equations Poiseuille equation · Pascal's law Viscosity (Newtonian · non-Newtonian) Buoyancy · Mixing · Pressure Liquids Surface tension Capillary action Gases Atmosphere Boyle's law Charles's law Gay-Lussac's law Combined gas law Plasma
Rheology Viscoelasticity Rheometry Rheometer Smart fluids Magnetorheological Electrorheological Ferrofluids
Scientists Bernoulli Boyle Cauchy Charles Euler Gay-Lussac Hooke Pascal Newton Navier Stokes

A rubber band is elastic, and can be stretched

Economic elasticity is at elasticity (economics)

Something that is elastic can be stretched or deformed (changed) and returned to its original form, like a rubber band. It tries to come back to its first shape. The stress is the force applied; the strain is how much the shape is changed, and the elastic modulus is the ratio between those numbers.

This idea was first suggested by Robert Hooke in 1675.