- the principal power spring of a mechanism, esp in a watch or clock
- the chief cause or motive of something
WordReference Random House Learner's Dictionary of American English © 2026
main•spring /ˈmeɪnˌsprɪŋ/USA pronunciation
n. [countable]
WordReference Random House Unabridged Dictionary of American English © 2026- Timethe principal spring in a mechanism, as in a watch.
- the chief force that causes movement, action, etc.:Unemployment was the mainspring of the discontent.
main•spring
(mān′spring′),USA pronunciation n.
- Timethe principal spring in a mechanism, as in a watch.
- the chief motive power;
the impelling cause.
- main1 + spring 1585–95
Collins Concise English Dictionary © HarperCollins Publishers::
mainspring /ˈmeɪnˌsprɪŋ/ n
'mainspring' also found in these entries (note: many are not synonyms or translations):