This is the 7972nd most frequent Turkish word.
kulübünün
"Of the club" or "club's" (possessive form).
The word 'kulübünün' here is in genitive case, showing ownership or association of the 'club' to 'university' (rendering 'the club of the university').
Ayşe, üniversite kulübünün etkinliklerine katılmayı seviyor.
Ayşe likes to participate in the activities of the university club.
Here, 'kulübünün' expresses possession, indicating that the players belong to or are associated with the 'sports club'.
Spor kulübünün oyuncuları turnuvaya hazır.
The players of the sports club are ready for the tournament.
In this sentence, 'kulübünün' again specifies the entity that owns or is associated with the 'meeting', which is the 'book club'.