hollering vs bellowing

hollering and bellowing both are nouns.

Word	Noun	Adjective	Verb	Adverb
hollering	Yes	No	No	No
bellowing	Yes	No	No	No

As nouns, hollering and bellowing are synonyms defined as:

hollering and bellowing: a very loud utterance (like the sound of an animal)

Other synonyms of hollering include bellow, holla, holler, hollo, holloa, roar, roaring, yowl.

hollering (noun)	bellowing (noun)
a very loud utterance (like the sound of an animal)	a very loud utterance (like the sound of an animal)