Algiers vs Algerian capital

Algiers and Algerian capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
Algiers	Yes	No	No	No
Algerian capital	Yes	No	No	No

As nouns, Algiers and Algerian capital are synonyms defined as:

Algiers and Algerian capital: an ancient port on the Mediterranean; the capital and largest city of Algeria

Algiers (noun)	Algerian capital (noun)
an ancient port on the Mediterranean; the capital and largest city of Algeria	an ancient port on the Mediterranean; the capital and largest city of Algeria