This is the 1893rd most frequent Portuguese word.
urbana
Urban.
In this sentence, 'urbana' is an adjective describing 'arquitetura', indicating that the architecture refers to urban areas.
A arquitetura urbana é fascinante.
Urban architecture is fascinating.
Here, 'urbana' functions as an adjective modifying 'área', specifying the nature of the area as being associated with a city or dense living environment.
Vivemos em uma área urbana com muitas facilidades.
We live in an urban area with many amenities.
In this usage, 'urbana' describes 'música', showing that the type of music is connected to urban themes and characteristics.