push button vs bell

push button and bell both are nouns.

Word	Noun	Adjective	Verb	Adverb
push button	Yes	No	No	No
bell	Yes	No	Yes	No

As nouns, bell is a hyponym of push button; that is, bell is a word with a more specific, narrower meaning than push button:

push button: an electrical switch operated by pressing
bell: a push button at an outer door that gives a ringing or buzzing signal when pushed

Other hyponyms of push button include bell push, buzzer, doorbell, horn button, mouse button, panic button, reset button.

push button (noun)	bell (noun)
an electrical switch operated by pressing	a hollow device made of metal that makes a ringing sound when struck
	a push button at an outer door that gives a ringing or buzzing signal when pushed
	the flared opening of a tubular device
	a percussion instrument consisting of a set of tuned bells that are struck with a hammer; used as an orchestral instrument
	the sound of a bell being struck
	the shape of a bell
	(nautical) each of the eight half-hour units of nautical time signaled by strokes of a ship's bell; eight bells signals 4:00, 8:00, or 12:00 o'clock, either a.m. or p.m.

push button (verb)	bell (verb)
	attach a bell to