sedan chair vs sedan

sedan chair and sedan both are nouns.

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

As nouns, sedan chair and sedan are synonyms defined as:

sedan chair (noun)	sedan (noun)
a closed litter for one passenger	a car that is closed and that has front and rear seats and two or four doors
	a closed litter for one passenger