Pronounced Bo-eth, "Boneth" is an alternative to the word "Both". They mean the same thing and can be used in the same context, but "Boneth" is funnier, especially when used on Mrs. Lightbody at LRGS (fitty). Note the silent "n" according to baby chubber Josh Ray.
"Which paper do we do miss, paper 1 or paper 2?"
Well... do boneth!