auto manufacturer vs car manufacturer

auto manufacturer and car manufacturer both are nouns.

Word	Noun	Adjective	Verb	Adverb
auto manufacturer	Yes	No	No	No
car manufacturer	Yes	No	No	No

As nouns, auto manufacturer and car manufacturer are synonyms defined as:

auto manufacturer and car manufacturer: a business engaged in the manufacture of automobiles

Other synonyms of auto manufacturer include auto maker, automaker, car maker, carmaker.

auto manufacturer (noun)	car manufacturer (noun)
a business engaged in the manufacture of automobiles	a business engaged in the manufacture of automobiles