newspaper vs publishing firm

newspaper and publishing firm both are nouns.

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

As nouns, publishing firm is a hypernym of newspaper; that is, publishing firm is a word with a broader meaning than newspaper:

Other hypernyms of newspaper include publisher, publishing company, publishing house.

newspaper (noun)	publishing firm (noun)
the physical object that is the product of a newspaper publisher	a firm in the publishing business
a daily or weekly publication on folded sheets; contains news and articles and advertisements
a business firm that publishes newspapers
cheap paper made from wood pulp and used for printing newspapers