caboose vs railcar

caboose and railcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
caboose	Yes	No	No	No
railcar	Yes	No	No	No

As nouns, railcar is a hypernym of caboose; that is, railcar is a word with a broader meaning than caboose:

caboose: a car on a freight train for use of the train crew; usually the last car on the train
railcar: a wheeled vehicle adapted to the rails of railroad

Other hypernyms of caboose include car, railroad car, railway car.

caboose (noun)	railcar (noun)
a car on a freight train for use of the train crew; usually the last car on the train	a wheeled vehicle adapted to the rails of railroad
the area for food preparation on a ship