parking lot vs car park

parking lot and car park both are nouns.

Word	Noun	Adjective	Verb	Adverb
parking lot	Yes	No	No	No
car park	Yes	No	No	No

As nouns, parking lot and car park are synonyms defined as:

Other synonyms of parking lot include park, parking area.

parking lot (noun)	car park (noun)
a lot where cars are parked	a lot where cars are parked