How To Determine Job Titles In An Organization Hierarchy

1) What are the major components in determining job titles to the organization hierarchy/structure?
2) When do you called a department & section? Why is one given the job title of a GM instead of Manager? Job titles are free, so one said. My boss give job titles based on his liking - a section head is called General Manager and a department head is called a Senior Manager????
3) What can i do to knock sense to him?

Dear Gracelynremy,
1) I would like to clear you the difference between position & job as follows:
Position: Manager , Executive etc., ( the cadre )
Job: Include the skills required to fill a position like Marketing Manager, HR Manager , Marketing Executive, HR Executive etc.,
2) Department & section
Department: HR Department, Risk Department
Section: sub-department like Recruiting, compensation, statutory & etc.,//// Credit risks, Audit risks & etc.,
3) Sit the Heads of your departments, discuss with them about the segmentation of Departments, sections, hierarcy of repoting (to design jobs & positions )
Hope this may be helpful to you.