what's the difference between bonzai and bonsai?

I may be confused, too, but I suspect all possible interpretations apply:

1. "Banzai!" as per kamikaze or a popular and silly UK Channel 4 program.

2. "Bonzer" as per the Aussie term of endearment.

3. "Bonsai" as per the little trees, or perfect miniature replicas.

But I'll leave it to the hound himself to describe how this all fits together.