Otherwise known as a postcard, poctsarcd was sometimes known as the little typo that made good. Belfast fan Walt Willis made it and Savannah, Georgia, faned Lee Hoffman elevated it to fannish fame.

Walt and LeeH were engaged in a fast and furious overseas correspondence, with long letters supplemented by shorter ones that passed each other in the mail, and in turn were added to by postcards. When there hadn't been any mail from LeeH in a while, Walt dashed off a postscript to one of his letters that asked, "What, no poctsarcds?"

LeeH replied that, alas, there were no poctsarcds to be had in her area — not even pitcuer poctsarcds. For years afterward, no one in fandom ever used a postcard again. Willis, tickled, used his letterpress to run off some poctsarcds, so labeled. He also supplied the definition: While postcards have the space for the message printed on one side and the space for the address on the other, with poctsarcds it's done precisely the other way around.

Fannish spelling being what it is, eventually poctsarcd evolved to poctsard.

Contributors: Dr. Gafia, others.

from Fancyclopedia 2 ca. 1959
An Irish crittur very like a postcard, except that where you write on one side of a postcard and address the other, you address one side of a poctsarcd and write on the other. It originated as a typo (in a letter from Leeh to Walt Willis), like other such useful expressions as silp and filk song. There are variants like pitcuer poctsarcds, too.