This is the 559th most frequent Slovenian word.
koroškem
"Koroškem" is the locative/dative form of "Koroška," which refers to the Carinthia region.
Here, 'Koroškem' is a locative form referring to the region of Koroška, meaning 'in Koroška'.
Na Koroškem je veliko gozdov.
In Koroška, there are many forests.
The word 'Koroškem' in this context is used to denote the location where the action took place, again as the locative case.
Obiskali smo prijatelja na Koroškem.
We visited a friend in Koroška.
'Koroškem' is employed here to indicate the location being considered, demonstrating its use in the locative case in a different context.