Ultimate Collectors Series. An irregular series of large LEGO Star Wars sets designed for older builders. Frequently used as a scale reference for LEGO fan creations that are larger than minifig scale. See also ISD.
Universal Character Set, details ...
Uniform Communication Standard. 
Unicode Conversion Support + Universal Character Set + User Coordinate System
Uniform Container Symbol.
The unconditional stimulus. Unconditional means not learned.
Uniform Container Symbol...Designation for product identification which generally utilizes bar codes and is imprinted on the product container or packaging.
Universal Character Set
acronym: Secretariat to the U.S. National Commission