capable of returning to its original length, shape, etc., after being stretched, deformed, compressed, or expanded: an elastic waistband; elastic fiber.
2.
spontaneously expansive, as gases.
3.
flexible; accommodating; adaptable; tolerant: elastic rules and regulations.
4.
springing back or rebounding; springy: He walks with an elastic step.
5.
readily recovering from depression or exhaustion; buoyant: an elastic temperament.
1653, coined in Fr. (1651) as a scientific term to describe gases, from Gk. elastos "ductile, flexible," related to elaunein "to strike, beat out," of uncertain origin. Applied to solids from 1674. The noun, "cord or string woven with rubber," is 1847, Amer.Eng.