capital of Italy vs Eternal City

capital of Italy and Eternal City both are nouns.

Word	Noun	Adjective	Verb	Adverb
capital of Italy	Yes	No	No	No
Eternal City	Yes	No	No	No

As nouns, capital of Italy and Eternal City are synonyms defined as:

capital of Italy and Eternal City: capital and largest city of Italy; on the Tiber; seat of the Roman Catholic Church; formerly the capital of the Roman Republic and the Roman Empire

Other synonyms of capital of Italy include Italian capital, Roma, Rome.

capital of Italy (noun)	Eternal City (noun)
capital and largest city of Italy; on the Tiber; seat of the Roman Catholic Church; formerly the capital of the Roman Republic and the Roman Empire	capital and largest city of Italy; on the Tiber; seat of the Roman Catholic Church; formerly the capital of the Roman Republic and the Roman Empire