An Active Directory container object used within domains. An organizational unit is a logical container into which users, groups, computers, and other organizational units are placed. It can contain objects only from its parent domain. An organizational unit is the smallest scope to which a Group Policy object (GPO) can be linked, or over which administrative authority can be delegated.
A type of entry that is used specifically for storing information on a section of an organization. It can represent a department or a group of people, for example, ou = Accounting Dept.