Oslo vs capital of Norway

Oslo and capital of Norway both are nouns.

Word	Noun	Adjective	Verb	Adverb
Oslo	Yes	No	No	No
capital of Norway	Yes	No	No	No

As nouns, Oslo and capital of Norway are synonyms defined as:

Oslo and capital of Norway: the capital and largest city of Norway; the country's main port; located at the head of a fjord on Norway's southern coast

Other synonyms of Oslo include Christiania.

Oslo (noun)	capital of Norway (noun)
the capital and largest city of Norway; the country's main port; located at the head of a fjord on Norway's southern coast	the capital and largest city of Norway; the country's main port; located at the head of a fjord on Norway's southern coast