Nilpotent

Nilpotent means that if you keep multiplying something by itself, eventually you get nothing. For example, if you took the number 2 and kept multiplying it by itself over and over again you would get 2, 4, 16, 256, 65536, and so on. Eventually, though, when you go far enough, you would end up with 0. That's nilpotent - when you keep multiplying something by itself you eventually get nothing.