- twilight zone - the lowest level of the ocean to which light can reach
--1 is a kind of ocean floor, ocean bottom, seabed, sea bottom, Davy Jones's locker, Davy Jones
- twilight zone, no man's land - 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"
--2 is a kind of ambiguity, equivocalness
- twilight zone, no man's land - 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"