Mechanical timekeeping device of great accuracy, particularly one used for determining longitude (see latitude and longitude) at sea. Early weight- and pendulum-driven clocks were inaccurate because of friction and temperature changes and could not be used at sea because of the ship's motion. In 1735 John Harrison invented and constructed the first of four practical marine timekeepers. The modern marine chronometer is suspended to remain horizontal whatever the inclination of the ship and differs in parts of its mechanism from the ordinary watch. A chronometer may provide timekeeping accurate to within 0.1 second per day. See also Ferdinand Berthoud.

This entry comes from Encyclopædia Britannica Concise.
For the full entry on chronometer, visit

Seen & Heard

What made you look up chronometer? Please tell us what you were reading, watching or discussing that led you here.

Get Our Free Apps
Voice Search, Favorites,
Word of the Day, and More
Join Us on FB & Twitter
Get the Word of the Day and More