car vs car seat

car and car seat both are nouns.

Word	Noun	Adjective	Verb	Adverb
car	Yes	No	No	No
car seat	Yes	No	No	No

car (noun)	car seat (noun)
a motor vehicle with four wheels; usually propelled by an internal combustion engine	a seat in a car
a wheeled vehicle adapted to the rails of railroad
where passengers ride up and down
the compartment that is suspended from an airship and that carries personnel and the cargo and the power plant
a conveyance for passengers or freight on a cable railway