electric car vs electric automobile

electric car and electric automobile both are nouns.

Word	Noun	Adjective	Verb	Adverb
electric car	Yes	No	No	No
electric automobile	Yes	No	No	No

As nouns, electric car and electric automobile are synonyms defined as:

electric car and electric automobile: a car that is powered by electricity

Other synonyms of electric car include electric.

electric car (noun)	electric automobile (noun)
a car that is powered by electricity	a car that is powered by electricity