publishing house vs publishing firm

publishing house and publishing firm both are nouns.

Word	Noun	Adjective	Verb	Adverb
publishing house	Yes	No	No	No
publishing firm	Yes	No	No	No

As nouns, publishing house and publishing firm are synonyms defined as:

Other synonyms of publishing house include publisher, publishing company.

publishing house (noun)	publishing firm (noun)
a firm in the publishing business	a firm in the publishing business