holloa vs hollo

holloa and hollo both are nouns.

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

As nouns, holloa and hollo are synonyms defined as:

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

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

holloa (verb)	hollo (verb)
	utter a sudden loud cry
	cry hollo
	encourage somebody by crying hollo