Helsinki vs capital of Finland

Helsinki and capital of Finland both are nouns.

Word	Noun	Adjective	Verb	Adverb
Helsinki	Yes	No	No	No
capital of Finland	Yes	No	No	No

As nouns, Helsinki and capital of Finland are synonyms defined as:

Helsinki and capital of Finland: the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center

Other synonyms of Helsinki include Finnish capital, Helsingfors.

Helsinki (noun)	capital of Finland (noun)
the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center	the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center