Origin of balance spring
First recorded in 1880–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for balance spring
The balance-spring is attached at its outer end to a fixed stud R, and at its inner end to staff of balance.
This balance compensates both for its own expansion and contraction, and that of the balance-spring.