Non-commissioned officer

A non-commissioned officer (NCO) is an enlisted member of an armed force who has been given authority by a commissioned officer. Starfleet non-commissioned officers includes all the grades of Petty Officer while Marine non-commissioned officers includes the rank of Corporal as well as all the grades of sergeant.

The non-commissioned officer corps is the "junior" management of the military. They serve as administrative or training personnel and as advisers to the officer corps. However, their most valuable function is as a link between the 'common soldier' and the commissioned officer, who is discouraged from developing too close personal relationships with his charges. Also because officers - other than those who join as enlisted soldiers and are later commissioned - begin their careers in a position of authority but lack practical experience, senior NCOs are also often responsible for giving them on-the-job training.