ferry vs car-ferry

ferry and car-ferry both are nouns.

Word	Noun	Adjective	Verb	Adverb
ferry	Yes	No	Yes	No
car-ferry	Yes	No	No	No

As nouns, car-ferry is a hyponym of ferry; that is, car-ferry is a word with a more specific, narrower meaning than ferry:

ferry: a boat that transports people or vehicles across a body of water and operates on a regular schedule
car-ferry: a ferry that transports motor vehicles

ferry (noun)	car-ferry (noun)
transport by boat or aircraft	a ferry that transports motor vehicles
a boat that transports people or vehicles across a body of water and operates on a regular schedule

ferry (verb)	car-ferry (verb)
travel by ferry
transport by ferry
transport from one place to another