Petty officers are usually sailors that have served at least several years in their respective navies.
The modern petty officer dates back to the Age of Sail in the Royal Navy.
This is because the midshipman was regarded as future sea officer, with the all-important social distinction of having the right to walk the quarterdeck.
Midshipmen wore distinctive uniforms, master's mates dressed respectably, and both behaved like officers.
Petty officers, like all senior rates, wear "fore and aft" rig.
Petty officer, second class is equivalent in paygrade to sergeant in the United States Army, Marine Corps, and Space Force, and staff sergeant in the United States Air Force.
In the Navy, Petty Officer, Third Class is the juniormost of the Non-Commissioned Officer ranks, and thus a sailor must demonstrate satisfactory performance in the previous rank (E-3) in the form of a favorable performance review(s) by his/her superiors, and the passing of an exam, in order to be promoted to PO3.
In the Navy, it is acceptable to refer to a Petty Officer as such, while in the Coast Guard, rating is always used.