geographical area vs Western Roman Empire

geographical area and Western Roman Empire both are nouns.

Word	Noun	Adjective	Verb	Adverb
geographical area	Yes	No	No	No
Western Roman Empire	Yes	No	No	No

geographical area (noun)	Western Roman Empire (noun)
a demarcated area of the Earth	the western part after the Roman Empire was divided in 395; it lasted only until 476