balloon vs billow

balloon and billow both are nouns.

Word	Noun	Adjective	Verb	Adverb
balloon	Yes	No	Yes	No
billow	Yes	No	Yes	No

As verbs, balloon and billow are synonyms defined as:

Other synonyms of balloon include inflate.

balloon (noun)	billow (noun)
large tough nonrigid bag filled with gas or heated air	a large sea wave
small thin inflatable rubber bag with narrow neck

balloon (verb)	billow (verb)
become inflated	become inflated
ride in a hot-air balloon	rise and move, as in waves or billows
	rise up as if in waves
	move with great difficulty