auto maker vs automaker

auto maker and automaker both are nouns.

Word	Noun	Adjective	Verb	Adverb
auto maker	Yes	No	No	No
automaker	Yes	No	No	No

As nouns, auto maker and automaker are synonyms defined as:

auto maker and automaker: a business engaged in the manufacture of automobiles

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

auto maker (noun)	automaker (noun)
a business engaged in the manufacture of automobiles	a business engaged in the manufacture of automobiles