sedan vs motorcar

sedan and motorcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
sedan	Yes	No	No	No
motorcar	Yes	No	No	No

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

sedan: a car that is closed and that has front and rear seats and two or four doors
motorcar: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of sedan include auto, automobile, car, machine.

sedan (noun)	motorcar (noun)
a car that is closed and that has front and rear seats and two or four doors	a motor vehicle with four wheels; usually propelled by an internal combustion engine
a closed litter for one passenger