Null means having no value; in other words null is zero, like if you put so little sugar in your coffee that it’s practically null. Null also means invalid, or having no binding force.
From the Latin nullus, meaning "not any," poor, powerless null is not actually there at all. Or if it was, it’s gone now. Because null is basically nothing, zip, zilch, nada, and nix. What could be worse? Maybe being "null and void," which is a legal term making something really, really null. Null is the base of the word nullify, which means to make something invalid or to cancel something out.