mainspring

noun

main·​spring ˈmān-ˌspriŋ 

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.

Recent Examples on the Web

But the patience required to bush out plates and repair antique mainsprings day after day isn’t something everyone is born with. —David Hudnall, Kansas City Star, 16 June 2025

The large mainspring barrel at 12 o’clock delivers a 96-hour power reserve, tracked by a linear indicator at 9. —Matthew Catellier, Forbes.com, 26 May 2025

The mainspring barrel was reconfigured into a flying arrangement to reduce the mass of the top bridge. —Anthony Demarco, Forbes.com, 1 Apr. 2025

The same motif is painted on the mainspring barrel cover Voutilainen’s workshop handled the hand guilloche at the center of the dial and the sun and moon decoration on the day and night indicator on the second time zone subdial. —Carol Besler, Forbes, 26 Mar. 2025

Word History

First Known Use

1591, in the meaning defined at sense 1

Rhymes for mainspring

• bowstring
• coiling
• downswing
• drawstring
• forewing
• hamstring
• lapwing
• offspring
• plaything
• shoestring
• texting
• upswing

Kids Definition

mainspring

noun

main·​spring ˈmān-ˌspriŋ 

1

: the principal spring in a mechanical device (as a watch or clock)

2

: the chief or most powerful motive or cause