This is the 3646th most frequent Polish word.
gdańskiej
"Of Gdańsk" (possessive or related to the city of Gdańsk).
In this sentence, 'gdańska' is a genitive singular feminine adjective indicating that the library is associated with Gdańsk.
Biblioteka gdańska jest jedną z największych w regionie.
The Gdańsk library is one of the largest in the region.
Here, 'gdańskiej' is in the locative singular feminine form, describing the specific location of the meeting.
Spotkanie odbędzie się w sali gdańskiej.
The meeting will take place in the Gdańsk hall.
In this case, 'gdańskiej' is also an adjective in the genitive singular form, providing context to the type of fleet discussed.