A fork of Rural Dictionary
A black uncle. One who is African American, or of African decent (black) and who has a very close friend or even a relative that is having a child. Thus, since they are black they consider themselves an uncle, but a black uncle or buncle.
One Seventh season, episode 2, Turk says to Carla, after hearing JD's baby is about to be born:
"I'm a buncle now."