petrol engine vs automobile

petrol engine and automobile both are nouns.

Word	Noun	Adjective	Verb	Adverb
petrol engine	Yes	No	No	No
automobile	Yes	No	Yes	No

petrol engine (noun)	automobile (noun)
an internal-combustion engine that burns gasoline; most automobiles are driven by gasoline engines	a motor vehicle with four wheels; usually propelled by an internal combustion engine

petrol engine (verb)	automobile (verb)
	travel in an automobile