Definition of "fnord"

(programming) A metasyntactic variable, similar to foo and bar.  examples

(Discordianism) A word (which may or may not be "fnord" itself) commonly held to be invisible to the conscious mind, but subliminally causing a sense of unease or sudden anger when encountered. So used in the Illuminatus! trilogy.  examples

(Discordianism) A word defined as having no definition.  examples