patrol wagon vs black Maria

patrol wagon and black Maria both are nouns.

Word	Noun	Adjective	Verb	Adverb
patrol wagon	Yes	No	No	No
black Maria	Yes	No	No	No

As nouns, patrol wagon and black Maria are synonyms defined as:

Other synonyms of patrol wagon include paddy wagon, police van, police wagon, wagon.

patrol wagon (noun)	black Maria (noun)
van used by police to transport prisoners	van used by police to transport prisoners