(chiefly US military slang) An otherwise unspecified time of night; some time when it is dark out.

(chiefly US military slang) Half an hour past 12(am) midnight, or more formal and exact would be 00:30; The practice of adding “dark” and “thirty” (30) can be used sometimes as a slang term in place of an otherwise specific time a time of night, meaning some time when it is dark out between 00:01 - 05:00 hours local time.

The dark space in a glow discharge that is adjacent to the cathode.

The dark space in a glow discharge that is between the negative glow and the positive column.

The dark space in a glow discharge between the cathode glow and the negative glow.

plural of Faraday dark space

plural of Aston dark space

plural of cathode dark space

Synonym of oh dark thirty

plural of dark jungle glory