Western Roman Empire vs geographical area

Western Roman Empire and geographical area both are nouns.

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

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