mainspring
noun
[ ˈmeɪnsprɪŋ ]
• the main agent of motivation.
• "innovation is the mainspring of the new economy"
Similar:
motive,
motivation,
impetus,
driving force,
incentive,
impulse,
cause,
prime mover,
reason,
origin,
fountain,
fount,
beginning,
root,
generator,
basis,
• the principal spring in a watch, clock, or other mechanism.
