Italian Republic vs Eternal City

Italian Republic and Eternal City both are nouns.

Word	Noun	Adjective	Verb	Adverb
Italian Republic	Yes	No	No	No
Eternal City	Yes	No	No	No

Italian Republic (noun)	Eternal City (noun)
a republic in southern Europe on the Italian Peninsula; was the core of the Roman Republic and the Roman Empire between the 4th century BC and the 5th century AD	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