RV vs camping bus

RV and camping bus both are nouns.

Word	Noun	Adjective	Verb	Adverb
RV	Yes	No	No	No
camping bus	Yes	No	No	No

As nouns, camping bus is a hyponym of RV; that is, camping bus is a word with a more specific, narrower meaning than RV:

RV: a motorized wheeled vehicle used for camping or other recreational activities
camping bus: a recreational vehicle equipped for camping out while traveling

Other hyponyms of RV include camper, motor home, beach buggy, dune buggy.

RV (noun)	camping bus (noun)
a motorized wheeled vehicle used for camping or other recreational activities	a recreational vehicle equipped for camping out while traveling