This is the 496th most frequent Greek word.
διευθυντής
Director; Manager; Principal.
In this sentence, 'διευθυντής' refers to the head manager or principal of the school.
Ο διευθυντής του σχολείου μίλησε στη συνέλευση.
The school principal spoke at the assembly.
Here, 'διευθυντής' is used to mean the manager of a specific department within an organization.
Μετά από την προαγωγή του, έγινε ο διευθυντής του τμήματος.
After his promotion, he became the manager of the department.
In this usage, 'διευθυντής' stands for a director or individual who holds overarching responsibility within an organization.