The World Association for the Development of Philately (WADP) and the Universal Postal Union (UPU) jointly conceived and developed the WADP Numbering System - WNS, which was launched on 1 January 2002.

Glossary of Philatelic Terms used

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The philatelic terms used in describing the attributes of each stamp registered in the World Numbering System (WNS) are explained for each heading. The other features of the site are also explained.

Design The basic design of the stamp is registered only and separate registration provided where the size of the designs vary by more that 10%. Small differences in colour and design are treated as warranting a separate registration; however stamps with different tabs or labels are not registered separately where the stamps are indistinguishable from each other when separated from their tabs or labels.

Miniature Sheets When a registered stamp is issued as part of a miniature sheet an image of the miniature sheet is provided by way of a link for each of the stamps appearing in that miniature sheet. The word ‘miniature sheet’ is highlighted in the detailed information page for each of the relevant stamps.

Theme Each stamp is allocated to at least one Theme in the standard WNS list based on the subject matter portrayed on the stamp and/or the purpose of issue of the stamp. The first level of Themes is supported by a more detailed list of themes at a second level to assist in searching for issues by themes.

Subject The subject entered is according to the information supplied by the Issuing Authority enhanced with additional information included to allow for ease of searching when the Keyword search function is used.

Dimensions (Width and Height) The horizontal and vertical measurements of each stamp are recorded to the nearest 0.5 mm. measuring the width and height of the stamp from the edges of the perforations. Stamps are measured upon registration and these measurements are used unless the Issuing Authority supplies more precise details.
The maximum width and height are given for irregular shaped stamps.

Denomination The ISO Currency code for each Issuing Authority is used throughout. Where non-denominated stamps are registered the terminology of the Issuing Authority is used e.g. Brev, 1st class, Europe, For Local Addresses Only (FLOA) etc.

Layout/Format The objective is to provide sufficient information in a standard terminology to enable the stamp to be identified. Where the stamp is issued in a gummed sheet this is described as a sheet stamp as well as the number of stamps contained in the sheet. Where the stamp is issued in other formats such as self-adhesive, booklets or coils this information is provided as supplied by the Issuing Authority. As there are several terms used for miniature sheets or souvenir sheets the standard terminology of miniature sheet is used. This term also provides a link on the website to a scanned image of the issued miniature sheet.

Printers The printer for each registered stamp is recorded when and as supplied by the Issuing Authority.

Perforations The perforation data is given as vertical then horizontal measurements using the international scale of the number of perforations occurring in each 2 cm. of the stamp measured to the nearest decimal place (e.g. 13.5 by 14 indicates 13.5 perforations per 2 cm for the horizontal side of the stamp and 14 perforations per 2 cm. for the vertical side).
Perforations are measured upon registration unless this information in provided by the Issuing Authority.

Contacting the Issuing Authority The Participating Issuing Authorities page on the WNS site includes a link to the Issuing Authority’s website when this link has been supplied by the Issuing Authority.

Stamp Issuing Programmes Where the stamp issuing programme for each year has been provided by the Issuing Authority it has been included on the WNS site and is available as a link at the head of the pages showing the stamps issued in that year.

Participating Issuing Authorities This section of the website is accessed from the Home page and provides a full list of Participating Issuing Authorities with the number of stamps issued each year from the date of their joining WNS. The detailed pages for each Issuing Authority can be accessed from these pages together with a link to the Issuing Authority’s own website where supplied.