sedan vs automobile

sedan and automobile both are nouns.

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

As nouns, automobile is a hypernym of sedan; that is, automobile 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
automobile: a motor vehicle with four wheels; usually propelled by an internal combustion engine

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

sedan (noun)	automobile (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

sedan (verb)	automobile (verb)
	travel in an automobile