doorbell
NounWordNet 3.0
Webster's Dictionary (GCIDE)
doorbell \doorbell\ n. a bell or other sounding device, actuated by a push button at an outer door; the push button activating the bell; alos, the ringing of such a bell; as, I was in the shower and didn't hear the doorbell.
Syn: bell, buzzer. [WordNet 1.5]