used-car lot vs car park

used-car lot and car park both are nouns.

Word	Noun	Adjective	Verb	Adverb
used-car lot	Yes	No	No	No
car park	Yes	No	No	No

As nouns, car park is a hypernym of used-car lot; that is, car park is a word with a broader meaning than used-car lot:

used-car lot: a parking lot where a dealer in used-cars displays cars for sale
car park: a lot where cars are parked

Other hypernyms of used-car lot include park, parking area, parking lot.

used-car lot (noun)	car park (noun)
a parking lot where a dealer in used-cars displays cars for sale	a lot where cars are parked