squad car vs police car

squad car and police car both are nouns.

Word	Noun	Adjective	Verb	Adverb
squad car	Yes	No	No	No
police car	Yes	No	No	No

As nouns, squad car and police car are synonyms defined as:

squad car and police car: a car in which policemen cruise the streets; equipped with radiotelephonic communications to headquarters

Other synonyms of squad car include cruiser, patrol car, police cruiser, prowl car.

squad car (noun)	police car (noun)
a car in which policemen cruise the streets; equipped with radiotelephonic communications to headquarters	a car in which policemen cruise the streets; equipped with radiotelephonic communications to headquarters