A buzzer is a device that makes a loud, sharp sound to get people's attention or signal that something has happened. Game shows use buzzers so contestants can signal when they know an answer. Basketball games end when the buzzer sounds, marking the exact moment time runs out. In school, a buzzer might ring to tell students when class is over.

Buzzers work differently from bells, which make a ringing sound. A buzzer makes a harsh, abrupt noise: a buzz or beep that cuts through other sounds. That's why they're perfect for situations where you need everyone to notice immediately. Some doorbells are buzzers, especially in apartment buildings. Emergency alarm systems often use buzzers because the sound is hard to ignore.

The word can also describe a last-second shot in basketball. A buzzer-beater is a shot that goes in just as time expires, winning the game at the final possible moment. These shots are thrilling because they represent clutch performance under maximum pressure.

When something happens “at the buzzer,” it means right at the deadline, with no time to spare, like finishing your homework just as your parent calls you to set the table for dinner.