Namespace

Active Directory is primarily a namespace, as is any directory service. A telephone directory is a namespace. A namespace is any bounded area in which a given name can be resolved. Name resolution is the process of translating a name into some object or information that the name represents. A telephone book forms a namespace in which the names of telephone subscribers can be resolved to telephone numbers. The NTFS file system forms a namespace in which the name of a file can be resolved to the file itself.

Active Directory forms a namespace in which the name of an object in the directory can be resolved to the object itself.