water fountain vs bubbler

water fountain and bubbler both are nouns.

Word	Noun	Adjective	Verb	Adverb
water fountain	Yes	No	No	No
bubbler	Yes	No	No	No

As nouns, water fountain and bubbler are synonyms defined as:

water fountain and bubbler: a public fountain to provide a jet of drinking water

Other synonyms of water fountain include drinking fountain.

water fountain (noun)	bubbler (noun)
a public fountain to provide a jet of drinking water	a public fountain to provide a jet of drinking water
	any of various devices in which air or some other gas is bubbled through a liquid