tree - technical definition

A hierarchical structure such as the organization of a company. The term is derived from the concept of tree branches. For example, in a company organization chart, the top of the tree is the starting point, or highest level, such as the executive office. Various departments are branches that stem from the highest level, with smaller sections branching off the departments.

Files and Folders and the Root
The term often refers to the file/folder hierarchy of a hard disk. In Windows, the Explorer utility is used to display these hierarchies, while Finder provides the same view in the Mac. In an application, menu options such as "view directory," "directory tree," "view tree" or simply "tree" also display the hierarchy.