zigamorph
/zig'*-morf/ 1. {Hex} FF (11111111) when used as a {delimiter}
or {fence} character. Usage: primarily at {IBM} shops.
2. [proposed] The {Unicode} non-character +UFFFF
(1111111111111111), a character code which is not assigned to
any character, and so is usable as end-of-string.
[{Jargon File}]