The topmost directory from which all other directories branch. In the DOS and OS/2 and Unix operating systems, this is represented as a single backslash character. For example, if you want to move to the root directory, you would issue the CD \ command in DOS. Confusingly, the root directory actually represents the top of the tree structure, mixing parts of the same metaphor. As you move from the root directory to the sub-directories, you are moving into branches.
