twilight zone

Meanings

1. A moving line that divides the daylit side and the dark night side of a planetary body.
2. A region or context located in between others and therefore not subject to their norms.
3. A deteriorating area surrounding a central business district.
4. Synonym of mesopelagic zone (“the part of the ocean where there is very minimal light, located below the photic epipelagic zone but above the aphotic bathypelagic zone.”).

1. To put or place into an indeterminate position; to be in an ambiguous, undetermined, or improper context.
2. To cause to daydream or zone out; to cause to lose attention to one's surroundings.

1. A region in which surreal, supernatural, or fantastic events occur.

1. To experience or perceive something bizarre or fantastic.
2. To behave or occur in a confusing or unexpected manner.

Etymology

Because such a zone (in the literal sense of the term) is twilit; see twilight § Etymology.