Do you understand that the page you linked, from mathworks, is talking about a data type? Do you know what MATLAB is? Do you understand anything else on the page you linked, or you just saw "empty matrix" and thought "aha!" Congratulations for having the answer. If you can't explain your answer though, that's your tough luck (life's like that). You've asked this question or one very like it a few times now. I don't think anyone understands the question, I know I don't.