Several hours earlier than the crack of dawn. Specifically, when you have to get up really early in the morning. See also dark times.
by KM March 10, 2004
If the crack-of-dawn is early, then the crack-of-the-crack-of-dawn is even earlier. Hence, crack-of-crack.
I gotta get up at the crack-of-crack tomorrow 'cause I'm driving to Bakersfield. No Chappelle show for me!
by DK March 11, 2004