fountain vs natural spring

fountain and natural spring both are nouns.

Word	Noun	Adjective	Verb	Adverb
fountain	Yes	No	No	No
natural spring	Yes	No	No	No

As nouns, fountain and natural spring are synonyms defined as:

Other synonyms of fountain include outflow, outpouring, spring.

fountain (noun)	natural spring (noun)
a plumbing fixture that provides a flow of water	a natural flow of ground water
an artificially produced flow of water
a structure from which an artificially produced jet of water arises
a natural flow of ground water