1. an electrical device that makes a buzzing sound as a signal or alarm
2. a person or thing that buzzes

Examples

• The buzzer sounded to signal the end of the basketball game.
• Press the buzzer to call the nurse.
• The apartment building has a buzzer system at the front door.
• The quiz show contestants raced to hit their buzzers first.
• A loud buzzer woke everyone up during the fire drill.
• The doorbell buzzer wasn’t working properly.