Leiden vs urban center

Leiden and urban center both are nouns.

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

Leiden (noun)	urban center (noun)
a city in the western Netherlands; residence of the Pilgrim Fathers for 11 years before they sailed for America in 1620	a large and densely populated urban area; may include several independent administrative districts