I think one good use for wikis would be a dictionary of postal terms and abbreviation list of sorts, so I’ll start one here. Feel free to edit this post to add your terms by clicking the EDIT button at the bottom of the post.
Ad card: (Short for: Advertising Card) A postcard featuring advertisement to a product or service. Sometimes these are given away for free.
Air Label: Blue stickers/labels used to identify mail that is to be sent by air mail.
ATC: Artist Trade Card - miniature piece of art that are traded around the world, usually handmade, size 64 mm × 89 mm
B/E: Blank in Envelope
Cancellation mark or Postmark: The rubber stamp mark that post offices make on top of postage stamps, to acknowledge the payment of postage, and/or deface the stamp to prevent further use.
Cancellation mark (an example)
Commemorative stamp - A postage stamp, often issued on a significant date such as an anniversary, to honor or commemorate a place, event, person, or object.
CCUN - Chinese Characters Series Postcards by PostcardsMarket.
COTW - Countries of the World by Houseofpostcards.
Definitive stamp - A postage stamp that is part of the regular issue of a country’s stamps, available for sale by the post office for an extended period of time and designed to serve the everyday postal needs of the country.
EU UID — «United in Diversity» Series Postcards by Postcards Market.
FDC: First Day Cover, is a postage stamp on a cover, postal card or stamped envelope cancelled on the first day the issue is authorized for use.
FOTW: Flags of the World, a series of flag-themed postcards printed by PostcardsMarket.
FOTW - card
GF: Greetings From, a series of country-themed postcards printed by PostalLove.
HPC: Happy Postcrossing Card, a series of country-themed postcards printed by Papersisters.
International Reply Coupon: A coupon that can be exchanged for one or more postage stamps representing the minimum postage for an unregistered priority airmail letter of up to twenty grams sent to another Universal Postal Union (UPU) member country. IRCs are accepted by all UPU member countries.
ICONs: Icons of Countries, a series of country-themed postcards printed by The Postcard House.
Joint Issue: A related issue of a postage stamp in 2 countries simultaneously.
selfprint, selfprinted - a postcard printed by the sender independently (i.e. not by a large printing house, not by a publishing house, etc.) There are many points of view regarding the definition of what exactly is a selfprint.
Same topic stamps:Stamps share the same topic(Olympic, Chinese lunar new year, etc.) issued in worldwide countries.
Prepaid postcard/cover - A postcard/cover with prepaid e-stamp.
Prepaid postcard/cover (example)
Prepaid postcard(Xinjiang is a beautiful place)
Prepaid cover(Height Measurement for Mount Qomolangma in 2020)
Postage Labels - A postage certificate printed by a postage machine marked with the name of the country, postage, and date of use. It has the same effect as a stamp and will not be cancelled after being pasted.
PPC - Permanent Pictorial Cancellation, Postcard with Pictorial Postmark, it’s done in many countries like, Australia, India, Japan, China, etc.
PWE - Postcard World Explorer Series PostcardsMarket.
PHQ Cards - postcards, which feature an enlargement of each of the stamps produced for a commemorative issue. They are issued by the British Post Office and some of the earlier ones were produced in very small quantities. For example, this one.
Large Letter/Big Letter Postcard - A postcard that has the name of a place shown as a series of very large letters, inside of each of which is a picture of that locale.
Maximum Card - A maximum card (also known as a maxi-card, or maxicard) is a postcard with a postage stamp placed on the picture side of the card where the stamp and card match or are in maximum similarity.The cancellation or postmark is usually related to the image on the front of the card and the stamp.
Miniature sheet: A miniature sheet / souvenir sheet / minisheet is a small group of postage stamps still attached to the sheet on which they were printed. They are usually special issues commemorating an event or a theme.
Mint stamp: A stamp in its original state of issue, unused, and has never been mounted.
MOTW: Maps of the World-themed postcards printed by Postcardmarket.
MCPS - Map Cover on Postcard Series by PostcardBazaar.
Cinderella Stamp: Anything resembling a postage stamp, but not issued for postal purposes by a government postal administration. Also called artistamp (combination of “artist” and “stamp”).
Illegal Stamp: Postage stamp-like labels issued in the names of existing independent countries or territories, but was not produced or printed by the postal administration of that country. Illegal stamps are not valid for postage anywhere in the world.
Pillar box: The British name for their iconic street post boxes. This name is also used in some other countries.
SSTG - Stationery Shops Travel Guide postcards and fb.
UPU: Universal Postal Union, a specialized agency of the United Nations (UN) that coordinates postal policies among member nations, in addition to the worldwide postal system.
W/E: Written in Envelope
W/S: Written and Stamped
WC Postcards - WordCloud Postcards, Postcard Series by Postcard Sisters and Itg.
WOW: What do you know about…, Cuisines of the World, Wonders of the World postcards printed by WOW-CARDS and Itg.
WPD: World Postcard Day. (It falls on 1st October of every year, see website.)
WT: World Travel, a series of country-themed postcards printed by Nisan.
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