pitter-patter vs rain

pitter-patter and rain both are nouns.

Word	Noun	Adjective	Verb	Adverb
pitter-patter	Yes	No	Yes	Yes
rain	Yes	No	Yes	No

As verbs, rain is a hypernym of pitter-patter; that is, rain is a word with a broader meaning than pitter-patter:

Other hypernyms of pitter-patter include rain down.

pitter-patter (noun)	rain (noun)
a series of rapid tapping sounds	anything happening rapidly or in quick successive
	water falling in drops from vapor condensed in the atmosphere
	drops of fresh water that fall as precipitation from clouds

pitter-patter (verb)	rain (verb)
make light, rapid and repeated sounds	precipitate as rain
rain gently

pitter-patter (adverb)	rain (adverb)
describing a rhythmic beating
as of footsteps