This is the 17395th most frequent Turkish word.
üyelerini
"Üyelerini" means "its/their members" in English.
In this sentence, 'üyelerini' refers to the members of the club ('Kulüp') in the accusative case, indicating the direct object of the action (inviting).
Kulüp üyelerini toplantıya davet etti.
The club invited its members to the meeting.
Here, 'üyelerini' again indicates the members of the group ('Grup') as the direct object, showing whom the leader informed.
Grup lideri, üyelerini projedeki ilerlemeler hakkında bilgilendirdi.
The group leader briefed its members about the progress in the project.
In this example, 'üyelerini' functions as the direct object of the action (supporting), referring to the members of the organization ('Organizasyon').