# mainspring

> English word · Noun · frequency rank #99,528

## Definitions
1. The principal spring of a clockwork mechanism, which drives it by uncoiling.
2. The most important reason for, or element of, something.

## Etymology
From main + spring. For figurative sense, compare spring (“source, origin”).

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/mainspring