buzzer vs doorbell

buzzer and doorbell both are nouns.

Word	Noun	Adjective	Verb	Adverb
buzzer	Yes	No	No	No
doorbell	Yes	No	No	No

As nouns, buzzer and doorbell are synonyms defined as:

buzzer and doorbell: a push button at an outer door that gives a ringing or buzzing signal when pushed

Other synonyms of buzzer include bell.

buzzer (noun)	doorbell (noun)
a push button at an outer door that gives a ringing or buzzing signal when pushed	a push button at an outer door that gives a ringing or buzzing signal when pushed
a signaling device that makes a buzzing sound