bellow vs hollo

bellow and hollo both are nouns.

Word	Noun	Adjective	Verb	Adverb
bellow	Yes	No	Yes	No
hollo	Yes	No	Yes	No

As nouns, bellow and hollo are synonyms defined as:

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

bellow (noun)	hollo (noun)
a very loud utterance (like the sound of an animal)	a very loud utterance (like the sound of an animal)

bellow (verb)	hollo (verb)
shout loudly and without restraint	utter a sudden loud cry
make a loud noise, as of animal	cry hollo
	encourage somebody by crying hollo