This is the 14156th most frequent Turkish word.
mühendisleri
"Engineers" (plural form).
The word "mühendisleri" serves as the object in the accusative case, indicating the engineers one might meet.
Mühendisleri ile tanıştınız mı?
Have you met with the engineers?
The word "mühendisleri" is used as the object of the sentence to specify "engineers" with a definite accusative case in the context of who are being congratulated.
Bu projede çalışan mühendisleri tebrik ederim.
I congratulate the engineers who worked on this project.
Here, "mühendisleri" refers to "engineers" with the possessive form, indicating they belong to the company.