Page "Petty officer, third class" Paragraph 10

Petty officers serve a dual role as both technical experts and as leaders.

Unlike the sailors below them, there is no such thing as an " undesignated petty officer.

" Every petty officer has both a rank and rating ( job, similar to an MOS or AFSC in other branches ).

The rank and rating combined are known collectively as a sailor's rate.

A petty officer's full title is a combination of the two.

Thus, a petty officer third class who has the rating of fire control technician is called a fire control technician third class.

The term petty officer is, then, only used in abstract, the general sense, when referring to a group of petty officers of different ratings, or when the petty officer's rating is unknown.