We use the word REDRUM throughout this guide to refer to killing and violence. If you really want to understand redrum, try this brief exercise. First, get some red lipstick (like Danny writes with in the movie, but not the book) and write REDRUM on a piece of paper. Now go into the bathroom and stand in front of the mirror. Turn off the lights. Hold up your piece of paper and say, "Bloody Mary" thirteen times. If you are still alive after that, turn on the light and look at your paper in the mirror. What does it say? It says, MURDER!
Simple enough, right? Maybe not. Consider this:
If we think of redrum symbolically, we can find an even more compelling reason. Redrum is, in a way, something positive. It means, symbolically, the reverse of murder. In the chapters titled "REDRUM" and "Jack and Wendy," Jack and Wendy both almost murder each other. Almost-murder, is kind of like the reverse of murder. It's murder averted, murder that doesn't come to pass. Redrum is the possibility of the reverse of murder – life.
At the same time, it holds within it the possibility of murder. The prophecy can go either way, depending on the choices Danny is too young to be forced to make. His decision to call in Halloran (arguably) saves Wendy and Jack from actually murdering each other. Danny's own courage and love in dealing with Jack saves Danny from being murdered by him. (True, Jack dies, but at least he doesn't have the burden of murder to take with him into the afterlife.) And Danny's decision not to stop his parents from going to the Overlook saves us from reading a (potentially) really boring book.