Petty Officer

Petty officer was an enlisted naval rank, a type of military rank used by the service organizations of different cultures. This title was senior to a crewman, and subordinate to a chief petty officer. In comparison to infantry ranking systems, this rank was approximately equivalent to the grade of Corporal. However, the Petty Officer 2nd Class rank was equivalent to that of Sergeant and the 1st Class rank was equivalent to that of Staff Sergeant.

This was the lowest rank considered to have the responsibility of a "noncommissioned officer." Personnel of this grade were usually referred to by their job title. In Starfleet, a petty officer could be referred to as yeoman, or as specialist.

There were usually individual grades of petty officers, differentiated as first, second and third class. This appellation could be added to either their rank or title (i.e. "petty officer first class," "specialist second class," or "yeoman third class").