u
u
u up
U-L
U2
u4e
u8
UAYA
UBS
UCE
UCWAP
UDH82BME
UDK
UDM
UFN
UFUF
UG2BK
UGC
UGFSU
UGTR
ultra-wideband
ultraviolet data
umfriend
UMK
UMTS
UN*X
uncuffing
under construction
under mouse arrest
underling
UNF
unfriend
unicorn
uninstalled
unique user
Unix
unknown zone
unlock
unmetered
unofficial site
UNOIT
unPC
unplugged
unstructured data
unsubscribe
UNT
UNTCO
unzip
UOK
up
UPC
upgradathon
upgrade
upgrade fever
upgrade path
uplink
upload
UPOD
upside
upskirting
upstream
ur
UR2K
URAPITA
URI
URL
URL tagging
URN
URSAI
URW
URWS
URYY4M
URZ
USB
USC
USCWAP
Usenet
user
user agent
user session
user-friendly
user-generated content
username
Using a previously cached copy version
USP
utility
utility computing
UTM
UTM code
UUEE
UUENCODE - UUDECODE
UV
UWIWU
UWM
UX