newspaper vs publishing company

newspaper and publishing company both are nouns.

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

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

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

newspaper (noun)	publishing company (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