the Hill vs Capitol Hill

the Hill and Capitol Hill both are nouns.

Word	Noun	Adjective	Verb	Adverb
the Hill	Yes	No	No	No
Capitol Hill	Yes	No	No	No

As nouns, the Hill and Capitol Hill are synonyms defined as:

the Hill and Capitol Hill: a hill in Washington, D.C., where the Capitol Building sits and Congress meets

the Hill (noun)	Capitol Hill (noun)
a hill in Washington, D.C., where the Capitol Building sits and Congress meets	a hill in Washington, D.C., where the Capitol Building sits and Congress meets