stopwatch
US /ˈstɑːp.wɑːtʃ/
UK /ˈstɑːp.wɑːtʃ/

1.
cronometro
a watch with a button that starts or stops the movement of the hands, used for measuring the time taken by an event
:
•
The coach used a stopwatch to time the runners.
L'allenatore ha usato un cronometro per cronometrare i corridori.
•
He clicked the stopwatch to begin the experiment.
Ha cliccato sul cronometro per iniziare l'esperimento.