national capital vs capital of Egypt

national capital and capital of Egypt both are nouns.

Word	Noun	Adjective	Verb	Adverb
national capital	Yes	No	No	No
capital of Egypt	Yes	No	No	No

national capital (noun)	capital of Egypt (noun)
the capital city of a nation	the capital of Egypt and the largest city in Africa; a major port just to the south of the Nile delta; formerly the home of the Pharaohs