noun Horology.

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

Origin of hairspring

First recorded in 1820–30; hair + spring
Also called balance spring. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for hairspring

Historical Examples of hairspring

British Dictionary definitions for hairspring



horology a very fine spiral spring in some timepieces, which, in combination with the balance wheel, controls the timekeeping
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012