This is the 4156th most frequent Portuguese word.
serrano
"Serrano" means "from or related to the mountains."
Here, 'serrano' is used to describe something belonging to or characteristic of mountainous regions.
O queijo serrano é uma especialidade típica das montanhas.
Serrano cheese is a typical specialty from the mountains.
In this sentence, 'serrana' (form of 'serrano') works as an adjective modifying 'vegetation', describing its relationship to mountain areas.
A vegetação serrana muda de acordo com a altitude.
The mountainous vegetation changes according to the altitude.
Here, 'serrano' is describing the type of wind, specifying that it originates or occurs in mountain areas.