A time to be ready that is considered too early in the morning. Usually, it is a time between 02:00 and 05:00 a.m.
Example One:
Director: Tomorrow's schedule begins at 05:00 a.m., so be ready by 04:30 a.m.
Employee (under his breath): Oh crap! Another Zero-Dark-Buffalo-Hour timing!

Example Two:
Employee One: What time do we have to be ready?
Employee Two: Zero-Dark-Buffalo-Hour
Employee One: Shit! I wanted to sleep in!
by 569 Clifford July 15, 2009
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