Source : WordNet®

twilight zone
     n 1: the lowest level of the ocean to which light can reach
     2: the ambiguous region between two categories or states or
        conditions (usually containing some features of both);
        "but there is still a twilight zone, the tantalizing
        occurrences that are probably noise noise but might
        possibly be a signal"; "in the twilight zone between humor
        and vulgarity"; "in that no man's land between negotiation
        and aggression" [syn: {no man's land}]

Source : Free On-Line Dictionary of Computing

twilight zone
     
        [IRC]  Notionally, the area of cyberspace where {IRC}
        operators live.  An {op} is said to have a "connection to the
        twilight zone".
     
        [{Jargon File}]