ululate vs howl

ululate is not a noun while howl is a noun.

Word	Noun	Adjective	Verb	Adverb
ululate	No	No	Yes	No
howl	Yes	No	Yes	No

As verbs, ululate and howl are synonyms defined as:

Other synonyms of ululate include roar, wail, yaup, yawl.

ululate (noun)	howl (noun)
	a long loud emotional utterance
	a loud sustained noise resembling the cry of a hound
	the long plaintive cry of a hound or a wolf

ululate (verb)	howl (verb)
emit long loud cries	laugh unrestrainedly and heartily
	make a loud noise, as of wind, water, or vehicles
	emit long loud cries
	cry loudly, as of animals