buzzer
//ˈbʌzər//
Noun
buzzerSingular
buzzersPlural
1
An electrical device that makes a buzzing sound, used as a signal or alarm.
Press the buzzer to let them know you have arrived.
2
A button or switch that activates such a device, especially one used to gain entry to a building.
Press the buzzer to enter the building.
3
A sound-making device used in game shows or sports to indicate the end of a time period or a correct/incorrect answer.
The contestant pressed the buzzer just before time ran out.