Reality

Reality is all in your head, in this sense might mean "being or existance". The Matrix is not an illusion, but a program that uses others imagination, sort of like a prision of ones mind. What is real, we don't exactly know what it is, because it's what your brain precieves as real. We might be in a simulation program just like The Matrix, we'll never know for sure, we believe only what our minds wants us to believe.