stopwatch
/ˈstɒpˌwɒtʃ/ · stop·watch
noun
- A handheld timepiece designed to measure the amount of time elapsed between its activation and deactivation. The swimmer checked the stopwatch to see if she had broken the record.
- A device, often digital, used in laboratories or sports to record precise time intervals. The chemist used a stopwatch to time the reaction for exactly 45 seconds.
verb
- To measure the duration of an event using a stopwatch. He stopwatched the sprint to determine the athlete's speed.
Did you know? The first modern stopwatch was invented in 1822 by French watchmaker Nicolas Mathieu Rieussec, who called his device a "chronometer" for timing horse races.