black Maria vs patrol wagon

black Maria and patrol wagon both are nouns.

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

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

Other synonyms of black Maria include paddy wagon, police van, police wagon, wagon.

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