the thirty minutes before nightfall, or the thirty minutes after night falls.basically the 1 hour time frame as it becomes dark.
i told david the party starts at dark-thirty.
by da trick biatch December 20, 2005
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It is actually o' dark-thirty. It is a military term refering to beinging somewhere before the sun rises
We have to go, we have PT (physical training)at 0' dark-thirty.
by Goldi December 21, 2005
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the hour of the day that it becomes dark so it could be a half hour before or a half hour after it gets dark
i told bobby and jonny boy to be at my house to suck some little dick at dark-thirty
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A humorous way to declare an unknown time in the wee hours of the morning. Especially used by military personnel to describe an unwanted time to be awake or awaken. Usually pronounced "oh" dark thirty.
"What time is morning formation?"

"Have no clue, oh dark thirty I imagine!"

Sgt. Hanson always has us up at zero dark thirty for our morning runs!
by echoseven75 November 30, 2013
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Military time designating an unspecified time after midnight but before sunrise. Normally used in reference to either the time one goes to sleep, wakes up, or has to be on-the-job. Usually quite a while before sunrise, i.e.: well before 0500 hours ( 5AM for you civilians )

The name is a play on the way 24-hour time is handled in the Military. Times are pronounced as numbers and written without colons, i.e.: 4:30PM is 1630H or "sixteen-thirty hours". Times between midnight and noon such as 4:00AM are written as 0400 and have the leading zero called out as "zero" or the letter "O", as in "o-four-hundred".
Example: We had to get up at o-dark-thirty to get the job done this morning.
by Princess Die December 1, 2005
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Long past dark. Much later than after dark.
The sun went down at eight. We were out until ten. We were out past dark thirty.
by Ranger Wordsmith August 3, 2015
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Early in the morning before the sun is up.
Used to define when you must get up and go somewhere in the early hours of the morning between 1:30am and 5:30am.

a time in the am around the half hour mark.
"You're leaving tomarow? Will I get a chance to see you?"
"Nahh, we're taking off at o dark thirty. You won't be up yet."
by Cloudyjuicebox April 28, 2006
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