used-car lot vs parking lot

used-car lot and parking lot both are nouns.

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

As nouns, parking lot is a hypernym of used-car lot; that is, parking lot 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
parking lot: a lot where cars are parked

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

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