pullulate vs hum

pullulate is not a noun while hum is a noun.

Word	Noun	Adjective	Verb	Adverb
pullulate	No	No	Yes	No
hum	Yes	No	Yes	No

As verbs, hum is a hypernym of pullulate; that is, hum is a word with a broader meaning than pullulate:

Other hypernyms of pullulate include buzz, seethe.

pullulate (noun)	hum (noun)
	a humming noise
	the state of being or appearing to be actively engaged in an activity

pullulate (verb)	hum (verb)
breed freely and abundantly	sing with closed lips
produce buds, branches, or germinate	make a low continuous sound
become abundant; increase rapidly	sound with a monotonous hum
move in large numbers	be noisy with activity
be teeming, be abuzz