Glossary

Glossary term	Definition
addressed premise	A permanent or non-permanent building structure with an address being a potential delivery point for Royal Mail. Examples of an addressed premise would be a house, a flat within a block of flats, a caravan site, a bollard to which several houseboats may be moored, or an organisation occupying the whole building.
building	A physical, walled structure connected to foundations that has, or will have, a roof. This definition includes buildings surveyed at foundation stage.
CPLC (Code-Point location coordinate)	A National Grid reference for each postcode unit. It is a two-dimensional coordinated point to a resolution of 1 metre. Coordinates are attributed from Gridlink using an accuracy hierarchy.
Country code	The code used by the Office of National Statistics to indicate the country in which the Code-Point georeference lies. This has replaced the PAF update date field.
Country Code	England E92000001 Scotland S92000003 Wales W92000004 N Ireland N92000002
Comma-separated values (CSV)	The CSV file format is commonly used to exchange data between different applications, for example, Microsoft Excel and Access. Being text files, CSV files can also be viewed in Notepad.
delivery point	A Royal Mail-defined point to which mail is delivered. This may be a property (private address), organisation, mailbox or even, very rarely, the name of an individual. These categories are derived from the Programmers’ Guide from Royal Mail. This is distinct from the addressed premise because there may be more than one organisation at an address.
Gridlink	Gridlink is the name given to a joined-up Government initiative involving Royal Mail, the Office for National Statistics, National Records of Scotland (NRS), Land & Property Services and Ordnance Survey. All these organisations are involved in the georeferencing of postcodes and the relating of postcodes to administrative and National Health Service areas and so on.
inward code or incode	See postcode.
matched address	An address, resulting from a match between the OS MasterMap Topography Layer data and PAF, which has been allocated a coordinate position. The match may be a result of either manual or automatic matching, the latter encompassing both full and ‘fuzzy logic’ matching.
National Grid reference (NGref)	The National Grid provides a unique reference system that can be applied to all Ordnance Survey maps of Great Britain. The map of Great Britain is covered by 100km by 100km grid squares, with the origin lying to the west of the Isles of Scilly. When a National Grid reference is quoted, the easting (left to right direction) is always given before the northing (upwards direction). A National Grid reference (to 1 m) will identify the spatial position of the CPLC.
non-geographic postcodes	Special non-geographic postcodes are allocated to single organisations who receive an exceptionally large amount of mail. These are included in Code-Point Open.
outward code or outcode	See postcode.
Postcode Address File (PAF)	PAF now contains the postal addresses and postcodes of approximately 28 million delivery points in Great Britain.
Postal Address Location Feed (PALF)	The PAL Feed is provided to Ordnance Survey from GeoPlace, who have geocoded the PAF feed from Royal Mail, using source coordinates from Local Authorities in England, Wales & Scotland and Ordnance Survey.
positional quality indicator (PQI)	The positional quality indicator is a flag used to indicate the positional accuracy of the coordinates allocated to each postcode record. There are seven PQI values for the positional quality of CPLCs.
postal address	A postal address is a delivery point that is currently receiving mail. There may be many delivery points within an individual building structure as shown in OS MasterMap Topography Layer data.
postcode	An abbreviated form of address made up of combinations of between six and eight alphanumeric characters. A postcode may cover between 1 and 100 addresses. The average number of addresses per postcode is 15.
postcode area	An area given a unique alphabetic coding by Royal Mail to facilitate the delivering of mail. The area is identified by one or two alpha characters at the start of the full postcode, the letters being derived from a town, city or district falling within the postcode area. There are, at present, 120 postcode areas in Great Britain, for example, SO for Southampton, MK for Milton Keynes, B for Birmingham or W for London West. The postcode area code constitutes the first part of the outward code.
postcode district	A sub-area of the postcode area, specified by the character sub-string within the first half of a full postcode, which may be numeric, alphabetic or alphanumeric; for example, 42 from MK42 6GH or 1A from W1A 4WW. There are approximately 2 986 postcode districts in Great Britain. Note: There are certain non-geographic districts. In these instances, a district code is allocated to cover all large users in the postcode area.
postcode sector	A sub-area of a postcode district, whose area is identified by the number third from the end of a full postcode. There are approximately 11 200 postcode sectors in Great Britain. An example of a postcode sector code is 3, from GU12 3DH.
postcode unit	A sub-area of a postcode sector, indicated by the two letters of the inward postcode, which identifies one or more small-user postcode delivery points or an individual large-user postcode. There are approximately 1.7 million postcode units in the UK.