station wagon vs motorcar

station wagon and motorcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
station wagon	Yes	No	No	No
motorcar	Yes	No	No	No

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

station wagon: a car that has a long body and rear door with space behind rear seat
motorcar: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of station wagon include auto, automobile, car, machine.

station wagon (noun)	motorcar (noun)
a car that has a long body and rear door with space behind rear seat	a motor vehicle with four wheels; usually propelled by an internal combustion engine