A battlebox is a set consisting of any amount of decks, finely tuned to fight each other. Im currently building such a battllebox for my kitchen table group, since we usually only play draft formats (cube draft, wizard's tower, sealed deck).
Designing a battlebox enables you to play with constructed decks in a group of people who possibly don't own decks themselves. Since we mostly play a game mode called "Hunter" these decks work good against each other.