Why is a Brazilian wax called a Brazilian?

The bikini panties tend to be very small and narrow, which means that only a small strip of pubic hair is covered by them. Presuming that the woman doesn't want hair sticking out the sides of her bikini, she then gets a waxing 'down there' that removes all but a small strip of hair, which would be compatible with the Brazilian bikini style.

Hence, a Brazilian!