1. UAPITA (You’re a pain in the ass)

2. UART (Universal Asynchronous Receiver/Transmitter)

3. UBE (Unsolicited Bulk E-mail)

4. ubiquitous computing

5. UBR (Unspecified Bit Rate)

6. Ubuntu

7. UCC (Uniform Code Council)

8. UCD (User-Centered Design)

9. UCE (Unsolicited Commercial E-mail)

10. UCP (Universal Communications Platform)

11. UCS (Universal Character Set)

12. UCS/WINS (Uniform Communication Standard)

13. UDA (Universal Data Access)

14. UDDI (Universal Description, Discovery and Integration)

15. UDF (Universal Disk Format)

16. UDMA (Ultra DMA)

17. UDP (User Datagram Protocol)

18. UEFI (Unified Extensible Firmware Interface)

19. UHF (Ultra High Frequencies)

20. UI (User Interface)

21. UICC (Universal Integrated Circuit Card)

22. UID (User ID, User Identifier)

23. ULS (User Location Service) server

24. Ultra ATA

25. Ultra SCSI

26. UltraNav

27. ULTRIX

28. UMB (Upper Memory Block)

29. UML (Unified Modeling Language)

30. UMM (UN/CEFACT Modelling Methodology)

31. UMPC (Ultra Mobile Personal Computer)

32. UMTS (Universal Mobile Telecommunications System)

33. UN/CEFACT (United Nations Centre for Trade Facilitation and Electronic Business)

34. UN/EDIFACT (United Nations rules for Electronic Data Interchange for Administration, Commerce and Transport)

35. UNC (Universal or Uniform Naming Convention)

36. unconditional jump

37. unicast

38. Unicode

39. UNII (Unlicensed National Information Infrastructure)

40. union (1)

41. union (2)

42. union (3)

43. UniPress Emacs

44. unique visitors

45. UnitedLinux

46. UNIVAC I (UNIVersal Automatic Computer I)

47. UNIX

48. UNIX socket

49. UNIX compress

50. UNIX System V Release 4.0

51. Unix-like operating system

52. UnixWare

53. unparsed entity

54. unsigned integer

55. unsigned number

56. unstructured overlay network

57. unzip

58. update

59. upgrade

60. uplink (1)

61. uplink (2)

62. upload

63. UPnP (Universal Plug and Play)

64. UPS (Uninterruptible Power Supply)

65. upstream

66. uptime

67. UPX (Ultimate Packer for eXecutable)

68. URI (Uniform Resource Identifier)

69. URL (Uniform Resource Locator)

70. URN (Uniform Resource Name)

71. usability

72. USB (Universal Serial Bus)

73. USB 2.0 (Universal Serial Bus 2.0)

74. USB drive (1)

75. USB drive (2)

76. USB drive (3)

77. USB flash drive

78. USB keyboard

79. USB Mass Storage

80. USB OTG (USB On The Go)

81. USB port

82. Usenet (User Network)

83. user

84. user account

85. user agent

86. user friendliness

87. user ID

88. user plane

89. user session

90. user sessions

91. user-level security

92. username

93. USIM (Universal Subscriber Identity Module)

94. UTF (Universal Transformation Format)

95. UTF-8 (8-bit UCS/Unicode Transformation Format)

96. utility

97. uTLD (unsponsored Top-Level Domain)

98. UTP (Unscreened Twisted Pair)

99. UTRAN (UMTS Terrestrial Radio Access Network)

100. UUcoding

101. UUCP (Unix-to-Unix Copy Protocol)

102. uuencode

103. uuencoding (Unix to Unix Encoding)

104. UUNET (UNIX to UNIX Network)

105. UW (You’re welcome)

106. UWC (Universal Wireless Consortium)

107. UXGA (Ultra Extended Graphics Array)