U
universal group
A group that can contain members from any domain and can be granted permissions to resources in any domain in the current domain forest.update sequence number
A type of identifier that is used to control replication between domain controllers in Windows 2000 and Windows Server 2003.UPN
See user principal name.user principal name
A logon name type of a user on a Windows 2000 or Windows Server 2003 network. The user principal name consists of the user object name used in Active Directory, followed by the at symbol (@) and then, typically, the Domain Name System parent domain. For example, JeffSmith in the Fabrikam.com domain tree might have the user principal name jeffsmith@fabrikam.com.USN
See update sequence number.