firehouse vs fire station

firehouse and fire station both are nouns.

Word	Noun	Adjective	Verb	Adverb
firehouse	Yes	No	No	No
fire station	Yes	No	No	No

As nouns, firehouse and fire station are synonyms defined as:

firehouse and fire station: a station housing fire apparatus and firemen

firehouse (noun)	fire station (noun)
a station housing fire apparatus and firemen	a station housing fire apparatus and firemen