What does "elastic" mean?

Elastic: Able to return quickly to a former state or condition, after being depressed or overtaxed; having power to recover easily from shocks and trials; as, elastic spirits; an elastic constitution. Elastic bitumen. (Min.) See Elaterite. -- Elastic curve. (a) (Geom.) The curve made by a thin elastic rod fixed horizontally at one end and loaded at the other. (b) (Mech.) The figure assumed by the longitudinal axis of an originally straight bar under any system of bending forces. Rankine. -- Elastic fluids, those which have the property of expanding in all directions on the removal of external pressure, as the air, steam, and other gases and vapors. -- Elastic limit (Mech.), the limit of distortion, by bending, stretching, etc., that a body can undergo and yet return to its original form when relieved from stress; also, the unit force or stress required to produce this distortion. Within the elastic limit the distortion is directly proportional to the stress producing it. -- Elastic tissue (Anat.), a variety of connective tissue consisting of a network of slender and very elastic fibers which are but slightly affected by acids or alkalies. -- Gum elastic, caoutchouc.