Simple Definition of mainspring
: the most important spring in a watch or clock
: the most important or powerful cause or part of something
Full Definition of mainspring
1 : the chief spring in a mechanism especially of a watch or clock
2 : the chief or most powerful motive, agent, or cause
Examples of mainspring in a sentence
Agriculture is the mainspring of their economy.
First Known Use of mainspring
MAINSPRING Defined for Kids
Definition of mainspring for Students
: the principal spring in a mechanical device (as a watch or clock)
Learn More about mainspring
Britannica.com: Encyclopedia article about mainspring
Seen and Heard
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