twilight zone

noun

1. the lowest level of the ocean that light can reach.
2. an ill-defined area between two distinct conditions, categories, etc., usually comprising certain features of both; an indefinite boundary:

   a twilight zone between fantasy and reality.

twilight zone

noun

1. any indefinite or transitional condition or area
2. an area of a city or town, usually surrounding the central business district, where houses have become dilapidated
3. the lowest level of the ocean to which light can penetrate

Word History and Origins

Origin of twilight zone¹

First recorded in 1905–10

Example Sentences

Scientists call this section of the ocean the “twilight zone” because the fish that inhabit it are basically living in darkness with only a small glimpse of light, Paig-Tran said.

From Los Angeles Times

The deep ocean, referred to as the “twilight zone”, is enormously mysterious.

From BBC

Her co-discoveries include how twilight zone fish make their skin intensely black and how the bodies of crustaceans called Cystisoma are so transparent they are almost completely invisible.

From National Geographic

“It’s like I’m in a twilight zone having to explain this to people.”

From Seattle Times

"The German economy looks set to remain in the twilight zone between minor contraction and stagnation not only this year but also next year," he said.

From Reuters