Capitol Building vs Capitol

Capitol Building and Capitol both are nouns.

Word	Noun	Adjective	Verb	Adverb
Capitol Building	Yes	No	No	No
Capitol	Yes	No	No	No

As nouns, Capitol Building and Capitol are synonyms defined as:

Capitol Building and Capitol: the government building in Washington where the United States Senate and the House of Representatives meet

Other synonyms of Capitol Building include United States Capitol.

Capitol Building (noun)	Capitol (noun)
the government building in Washington where the United States Senate and the House of Representatives meet	the government building in Washington where the United States Senate and the House of Representatives meet