This is the 4577th most frequent Turkish word.
başlamasının
"The act of starting (of something)."
In this sentence, 'başlamasının' is the third-person possessive form of the verbal noun 'başlama' (beginning, start), implying possession or relation to the film.
Film başlamasının ardından salon sessizleşti.
After the film's beginning, the room became silent.
Here, 'başlamasının' represents the initiation or commencement of a plural subject ('projects') with the possessive suffix indicating a relationship.
Projelerin başlamasının ardından süreç hızlandı.
After the start of the projects, the process sped up.
In this example, 'başlamasının' denotes the act of starting of a novel, combined with a possessive suffix to show it belongs to 'kitap' (book).