U

Unicode
A 16-bit character set capable of encoding all known characters and used as a worldwide character-encoding standard. Windows NT� uses Unicode exclusively; Windows� 95 and Windows� 98 do not.
universal well-known security identifier (SID)
A SID that is meaningful on all secure systems using the security model implemented in Windows NT�.
user-defined pen
A cosmetic or geometric pen that uses a unique series of dashes, dots, or dashes and dots defined by the user. See also cosmetic pen, geometric pen.
UTC
See Coordinated Universal Time.