Bydgoszcz vs urban center

Bydgoszcz and urban center both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bydgoszcz	Yes	No	No	No
urban center	Yes	No	No	No

Bydgoszcz (noun)	urban center (noun)
an industrial city and river port in northern Poland	a large and densely populated urban area; may include several independent administrative districts