Some of the many acronyms and abbreviations:

CEO

Civil Enforcement Officer – Civil Enforcement Officers, previously “Parking Attendants”, are employed by or on behalf of councils to enforce parking restrictions. They may have other related duties as well, such as littering enforcement. Sometimes known as “Traffic Wardens”, but this title is officially a position employed by the police.

CPZ

Controlled Parking Zone – an area where signs at the entrance set times for the restrictions within it. Within a CPZ you may find single yellow lines without the normal time plates, as the restriction times are specified on the zone entrance plates. The zone may also set days and/or hours that pay & display tariffs operate or permits are required. Often used for stadiums, where restrictions apply on event days, or pay and display zones around town centres.

NtO

Notice to Owner – part of the process a PCN goes through, where the registered keeper of a vehicle is written to inform them they have a limited amount of time to pay or appeal a notice.

PCN

Penalty Charge Notice – a parking ticket issued by (or on behalf of) a local authority. These are civil penalties, created to give councils a way of enforcing parking restrictions without the end result of going through the criminal justice process. Whilst some dangerous parking can still result in the motorist getting a criminal conviction, a PCN will not. Private parking companies often use “Parking Charge Notice” abbreviated the same way – these also do not go through the criminal courts, but follow a different set of laws to the council issued PCNs.

PPA

Permit Parking Area – a zone where permits are required to park, but with no bays. Used mainly in residential areas to prevent people from outside the area parking, without the clutter and cost of using permit bays.

RPZ

Restricted Parking Zone – a different type of area where signs at the entrance set restrictions within the zone, but with these, there is no need for lines within the zone – it creates a “no waiting” restriction as if yellow lines were painted through the area. There may be exemptions for “except within marked bays”, and may ban loading some or all of the time as well. Often used in pedestrian zones to avoid painting yellow lines along historic or vehicle-free streets.

TMO

Traffic Management Order – These are the same as TROs, but for within London

TRO

Traffic Restriction Order – Parking restrictions are not just the lines and signs; they have to be backed up by documents called Traffic Restriction Orders, written, advertised, and published by the local authority. TROs are also used to set other restrictions such as speed limits, one-way streets, and banned turns – nearly every sign that isn’t a direction sign has (or should have) a TRO backing it. These are called TMOs in London