A combination of calling your friend a dude and bro at the same time, you don't know rather to call your friend a dude or bro and it just slips out being called Bude.
*At Waffle House Man one turns to man two: Hey Bude guess what?
Man Two: did you just call me Bude?
Man one: I think I did I was going for a combo of both bro and dude
Man two: Bude we need to start saying this
A close friend who you usually hang out with.
This person may be clever or mentally retarded; as long as he is your buddy, you can refer to him as a bude.