doorbell
n. countable A1 Beginner US //ˈdɔɹˌbɛɫ// UK //dˈɔːbɛl// door·bell
n. a button outside a house that you press to make a sound inside, telling the people you are there.
n. a signalling device, typically located near an exterior door, that a visitor activates to alert occupants of their presence.
I heard the doorbell ring while I was in the kitchen.
The delivery driver rang the doorbell twice before leaving the package on the front porch.
Modern security systems often integrate the doorbell with a high-definition camera, allowing homeowners to communicate with visitors remotely via a smartphone application.
From door + bell.