Chief Petty Officer is the seventh enlisted rank in the U.S. Navy and U.S. Coast Guard, just above
Petty Officer First Class and below
Senior Chief Petty Officer, and is a senior non-commissioned officer. The Grade of Chief Petty Officer was established on April 1, 1893.
Unlike Petty Officer First Class and lower ranks, advancement to Chief Petty Officer not only carries requirements of time in service, superior evaluation scores, and specialty examinations, but also carries an added requirement of peer review. A Petty Officer First Class can only advance after review by a selection board of serving Senior and Master Chief Petty Officers, in effect "choosing their own" and conversly not choosing others.
Advancement into the Chief Petty Officer grades is the most significant promotion within the enlisted naval ranks. At the rank of Chief, the sailor takes on more administrative duties. In the Navy, their uniform changes to reflect this change of duty, becoming similar to that of an officer albeit with different insignia. (In the Coast Guard, petty officers, chief petty officers, warrant officers, and commissioned officer all wear similar uniforms.) Sailors in the three Chief Petty Officer ranks also have conspicuous privileges such as separate dining and living areas. Any naval vessel of sufficient size has a room or rooms that are off-limits to anyone not a Chief (including officers) except by specific invitation (if one is invited to eat in the Chief's Mess, it is customary to eat everything on the plate no matter what condiments are added by members of the Chief's Mess to enhance one's dining experience). In Navy jargon, this room is called the Chief's Mess, or tongue in cheek, the "goat locker." In addition, a Chief Petty Officer, no matter how much he was on "first name" basis with other petty officers before promotion, is always addressed as "Chief" by subordinates and superiors.
Chief Petty Officers serve a dual role as both technical experts and as leaders, with the emphasis being more on leadership as they progress through the CPO ranks. A recognized, collateral duty for all chiefs is the training of Junior Officers. Like Petty Officers, every chief has both a rate (rank) and rating (job, similar to an MOS in other branches). A chief's full title is a combination of the two. Thus, a Chief Petty Officer, who has the rating of Gunner's Mate would properly be called a Chief Gunner's Mate.
Each rating has an official abbreviation, such as QM for Quartermaster, BM for Boatswain's Mate, or GM for Gunner's Mate. When combined with the petty officer level, this gives the short-hand for the chief's rank, such as BMC for Chief Boatswain's Mate. It is not uncommon practice to refer to the chief by this short hand in all but the most formal correspondence (such as printing and inscription on awards). Mostly, though, they are simply called "Chief," regardless of rating.
The rating insignia for a CPO is an eagle with spread wings above three chevrons. The chevrons are topped by a rocker that goes behind the eagle. This is used on the Dress Blue and Aviation Working Green uniforms. On all other uniforms, the insignia used is the one that has become universally accepted as the symbol of the Chief Petty Officer. This is a fouled (entwined in the anchor chain) gold anchor superimposed with a silver "USN" in the Navy or a silver shield in the Coast Guard.
In the Navy, officers and chiefs are referred to as "khakis." This is a reference to the color of their most common shipboard "working" uniforms, and is a direct contrast to those in paygrades E-6 and below (deckplate sailors or, blueshirts). In the Coast Guard, petty officers, chief petty officers, warrant officers, and commissioned officer all wear similar uniforms.