This is the 2553rd most frequent Polish word.
pomorskiej
"Pomorskiej" means "of Pomerania" or "Pomeranian" (relating to the Pomorskie region in Poland).
In this sentence, 'pomorski' is used as an adjective to describe the university as belonging to the Pomeranian region.
Studiuję na Uniwersytecie Pomorskim w Polsce.
I study at the Pomeranian University in Poland.
The word 'Pomorskiej' functions as an attributive adjective in the genitive case to describe the 'Land' regarding a historical context.
Mapa przedstawia historię Pomorskiej Krainy.
The map shows the history of the Pomeranian Land.
'Pomorskiej' modifies 'village' and indicates that it is in the Pomeranian region, here in the locative case.