1. <convention> A word used in electronic mail and news messages to tag utterances as surrealist mind-play or humour, especially in connection with Discordianism and elaborate conspiracy theories. "I heard that David Koresh is sharing an apartment in Argentina with Hitler. (Fnord.)" "Where can I fnord get the Principia Discordia from?"
2. <programming> A metasyntactic variable, commonly used by hackers with ties to Discordianism or the Church of the SubGenius.
The word "fnord" was invented in the "Illuminatus!" trilogy by Robert Shea and Robert Anton Wilson.