balance spring

noun

, Horology.

1. hairspring.

Word History and Origins

Origin of balance spring¹

First recorded in 1880–85

Example Sentences

The balance-spring is attached at its outer end to a fixed stud R, and at its inner end to staff of balance.

From Project Gutenberg

This balance compensates both for its own expansion and contraction, and that of the balance-spring.

From Project Gutenberg