U

Acronym	Definition
U	Underlined
U	University
U	Unsatisfactory
U	Upper
U	You
U	Atomic Unit (measure of mass)
U	Envelope or Letter Sheet (Scott Catalogue prefix; philately)
U	Kosher (from Union of Orthodox Hebrew Congregations)
U	Sunday (one letter abbreviation for day of week)
U	Ultra
U	Umbrella
U	Umdrehungen (German: RPM)
U	Umpire
U	Unclassified
U	Uncle
U	Uncleared
U	Und (German: And)
U	Unified
U	Uniform (aviation letter code)
U	Union Metallic Cartridge Co (division of Remington Arms; used on head stamp of .22 cartridges)
U	Unit
U	Unit of measurement for rackmount equipment (U is 1.75in or 4.44cm)
U	Unitary (mathematics)
U	United
U	Universal
U	Unknown Wind Intensity (weather reports)
U	Unlimited Time (broadcasting operating schedules)
U	Unsymmetrical
U	Unterseeboot (German: submarine)
U	Update(d) (action code)
U	Upper Class
U	Uracil
U	Uranium
U	Urgent
U	US DoT tire speed rating (124 mph)
U	Used
U	Utah (ammunition headstamp)
U	Utility
U	Utility (US military aircraft designation; as in U-6 Beaver)
U	Wind Speed