1. A fine, spiral spring in a watch or clock that regulates the oscillation of the balance wheel and controls the rate of timekeeping.
Usage: technical; horology

Examples

• The watchmaker carefully adjusted the hairspring to improve the accuracy of the timepiece.
• A broken hairspring can cause a watch to lose or gain time significantly.
• The hairspring works in tandem with the balance wheel to regulate the watch's movement.
• Precision manufacturing of hairsprings requires specialized equipment and expertise.
• Even a tiny dust particle on the hairspring can affect the watch's performance.