A timer is a device that measures how much time passes and often signals when that time is up. Kitchen timers help cooks know when cookies are done baking by beeping after, say, twelve minutes. Sports referees use timers to track quarters or halves of games. Board games like chess use timers to limit how long each player can think before moving.

Timers can be simple mechanical devices you twist to set, digital gadgets that count down on a screen, or apps on phones and computers. A simple hourglass is a kind of timer: when all the sand flows from top to bottom, you know a specific amount of time has passed.

People use timers to stay focused and manage their work. A student might set a timer for twenty minutes of homework, knowing they can take a break when it goes off. Teachers use timers during classroom activities. Athletes use interval timers during training to alternate between hard exercise and rest periods.

The word can also describe a person who records times, like a timer at a swim meet who clicks a stopwatch when each swimmer touches the wall. Without timers, we'd have to guess how long things take, which would make cooking, sports, and countless other activities much harder to manage well.