also: タイマ
timer; time switch
General device for measuring or controlling time, such as a kitchen timer or an automatic on/off switch.
Please set a timer while cooking.
This light turns off automatically with a timer.
stopwatch
Specifically a stopwatch for measuring elapsed time, often used in sports or experiments.
I time my runs with a stopwatch.
timekeeper
A person who keeps time, such as in a game or competition; less common than the device meanings.
The timekeeper in a match must manage the time accurately.
self-timer; delay timer
Abbreviation of セルフタイマー; used in photography for the delayed shutter release.
See also: セルフタイマー
Let's use the self-timer when taking a group photo.
I set a 5-minute timer and boiled the eggs.
The timer went off, so I took the dish out of the oven.
I stopped the stopwatch the moment the runner crossed the finish line.
I set a timer for 30 minutes and focused on studying.
full-timer; full-time worker