zigamorph

zigamorph /zig'*-morf/ n.  1. Hex FF (11111111) when used
   as a delimiter or {fence} character.  Usage: primarily at IBM
   shops.  2. [proposed] n. The Unicode non-character +UFFFF
   (1111111111111111), a character code which is not assigned to any
   character, and so is usable as end-of-string.  (Unicode (a subset
   of ISO 10646) is a 16-bit character code intended to cover all of
   the world's writing systems, including Roman, Greek, Cyrillic,
   Chinese, hiragana, katakana, Devanagari, Easter Island
   `rongo-rongo', and even {elvish}.)