- [usually singular] mainspring (of something) (formal)
the most important part of something; the most important influence on something 主体部分;主要影响 Small companies are the mainspring of the British economy. 小公司是英国经济的主体。 Her Christian faith was the mainspring of her life. 她的基督教信仰是她生活的主要动力。
the most important spring in a watch, clock, etc. (钟表等的)主发条