hairspring

American  

[hair-spring] / ˈhɛərˌsprɪŋ /

noun

Horology.

1. a fine, usually spiral, spring used for oscillating the balance of a timepiece.

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hairspring British  

/ ˈhɛəˌsprɪŋ /

noun

1. horology a very fine spiral spring in some timepieces, which, in combination with the balance wheel, controls the timekeeping

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Etymology

Origin of hairspring

First recorded in 1820–30; hair + spring

Example Sentences

Its hairspring, mainspring, ruby bearings and a few other parts were sourced from Switzerland.

From Los Angeles Times • May 22, 2023

However, Shapiro said, the production version of Resurgence will include a hairspring and bearings made in America.

From Los Angeles Times • May 22, 2023

It is intended to be the first member of a family of movements incorporating both the DIAMonSIL escapement and an adjustable oscillator fitted with a silicium hairspring.

From New York Times • Nov. 23, 2012

Since the 17th century they have depended on a delicate hairspring that keeps a balance wheel turning backward and forward at a regular rate.

From Time Magazine Archive

What I have said regarding it, however, gives an idea of how a hairspring should be pinned.

From Scientific American Supplement, No. 664, September 22,1888 by Various