Resilience entered English in the 1620s, borrowed from the Latin verb resilire, whose two halves quite literally add up to "jump back": the prefix re- supplies the "back," and salire — the same leaping root buried inside salient and sally — supplies the "jump." For its first two centuries in English, resilience stayed a fairly abstract, literary idea: the general notion of something snapping back.

Then, by 1824, resilience got drafted into physics and engineering, where it still lives today — the precise, measurable ability of a material like steel, rubber, or a diving board to absorb a shock and spring back to its original shape instead of staying bent or breaking. It took until the 1970s, when psychologist Norman Garmezy began studying children who thrived despite deeply stressful childhoods, for resilience to get borrowed a second time — out of materials science and into psychology, to describe people instead of springs. Two centuries as a stress test for beams and bridges, and now it's mostly about you.