At a moment's notice

Origin

The phrase "at a moment's notice" first sprang into common English usage in the early 19th century, a vivid expression born from the clash of two distinct ideas. The word "notice" carried the weight of a formal warning, a period of time thoughtfully granted—like a landlord's notice to quit or a military order outlining future movements. But then, this structured, deliberate "notice" was brutally compressed. It was reduced to a mere "moment," the briefest imaginable sliver of time. This linguistic combination forged a potent image: the absolute lack of warning, the demand for instant readiness without any prior preparation. It perfectly encapsulated the urgency of a rapidly industrializing world, a need for swift action that could appear in anything from a sudden military deployment to an unexpected market shift, cementing its place as the go-to phrase for immediate, unhesitating response.