This is the 3802nd most frequent Turkish word.
örgütüne
"Örgütüne" means "to his/her/its organization" in English.
In this sentence, 'örgütüne' refers to a specific organization (the environmental organization), and is used with the dative suffix '-e' indicating direction or association.
Yerel çevre örgütüne katılmayı düşünüyorum.
I am thinking about joining the local environmental organization.
Here, 'örgütüne' again refers to a specific organization, but the context indicates ownership or association with activities mentioned in the statement.
Resmi belgeler, örgütüne ait faaliyetleri detaylı olarak göstermektedir.
The official documents detail the activities belonging to the organization.
In this instance, 'örgütüne' suggests association with a specific organization, qualified by the descriptive term 'terror' in the statement.