seconds pendulum

noun

: a pendulum requiring exactly one second for each swing in either direction or two seconds for a complete vibration and having a length between centers of suspension and oscillation of 99.353 centimeters at sea level in latitude 45 degrees

The Ultimate Dicitonary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now