o-dark-thirty

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 2, 2005

o dark thirty

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 May 9, 2006

O dark -thirty

Very early. Early enough to seriously fuck up the day before, and the day of the event in question.

Yo...we had to get up at O dark -thirty to get to the meeting on time.

by Rick Burns December 23, 2006