Mainspring

Part of speech: noun

Definitions

1. A coiled spring that powers the movement of clocks or watches ; the chief force or reason behind an action or event
2. The main mechanical spring that stores energy to drive a mechanism ; the principal factor that motivates behavior or decisions
3. The essential spiral spring which supplies power to timepieces ; the central cause or stimulus prompting a particular response or activity

Etymology: "Mainspring" is a compound of "main," meaning chief or principal, and "spring," the coiled strip of metal that stores energy. The mechanical sense came first: the mainspring is the large spring in a clock or watch that, when wound, releases its stored force to drive the gears. Because it was the component that powered everything else, the term became a natural metaphor for whatever drives a process. The figurative sense draws on an older meaning of "spring" as a source or origin, the same sense found in phrases like "the spring of a river." Put together, the main spring is the chief source from which motion or action flows. A mechanism needs one powerful store of energy to keep going, and a person's behavior is likewise described as having one principal motive that sets the rest in motion.

Synonyms: spring, driving force, core, basis

Antonyms: ineffectiveness, ineptitude