bandwagon vs wagon

bandwagon and wagon both are nouns.

Word	Noun	Adjective	Verb	Adverb
bandwagon	Yes	No	No	No
wagon	Yes	No	No	No

As nouns, wagon is a hypernym of bandwagon; that is, wagon is a word with a broader meaning than bandwagon:

bandwagon: a large ornate wagon for carrying a musical band
wagon: any of various kinds of wheeled vehicles drawn by an animal or a tractor

Other hypernyms of bandwagon include waggon.

bandwagon (noun)	wagon (noun)
a large ornate wagon for carrying a musical band	any of various kinds of wheeled vehicles drawn by an animal or a tractor
a popular trend that attracts growing support	a car that has a long body and rear door with space behind rear seat
	van used by police to transport prisoners
	a child's four-wheeled toy cart sometimes used for coasting