This is the 14683rd most frequent Turkish word.
projelerinin
"Of his/her/its/their projects."
The word 'projelerinin' is used in possessive form here, indicating whose projects are being referred to, in this case, 'their'.
Projelerinin teslim tarihi yaklaştı.
The submission date of their projects is approaching.
'Projelerinin' here indicates possession, referring to 'your' as the owner of 'projects' when speaking formally or respectfully.
Projelerinin kapsamını yeniden gözden geçirdik.
We reviewed the scope of your projects again.
This usage of 'projelerinin' once more shows possessiveness, denoting 'your' in formal or plural contexts.