2. X Bitmap
3. X Pixelmap
4. X protocol
5. X server
6. X Toolkit
7. X Window (X Window System)
8. X.225
9. X.25
10. X.400
11. X.500
12. X.509
13. X+V
14. X11
15. X12ANSI
16. X2
17. X3.92 standard
18. x86
19. x86 emulator
20. Xandros
21. XAPIA (X.4.00 API Association)
22. XBL (eXtensible Binding Language)
23. XDI (XRI Data Interchange)
24. XDOS
25. xD-Picture Card
26. XDR (eXternal Data Representation)
27. XDR (XML-Data Reduced)
28. xDSL
29. XEmacs
30. Xeon
31. Xfce
32. XFDL Extensible Forms Description Language
33. XGA (Extended Graphics Array)
34. XHTML (Extensible Hypertext Markup Language)
35. XHTML+Voice
36. XIP (eXecute In Place)
37. XLib (X LIBrary)
38. XLR connector
39. XML (Extensible Markup Language)
40. XML database
41. XML document
42. XML namespace
43. XML parser
44. XML processor
45. XML Schema
46. XML Schema Language
47. XML tag
48. XML vocabulary
49. XML-Data
50. XML-RPC (eXtensible Markup Language-Remote Procedure Call)
51. Xmodem
52. XMS (eXtended Memory Specification)
53. XNOR (eXclusive NOR)
54. XOR
55. XPath (XML PATH Language)
56. XPCOM (Cross Platform Component Object Model)
57. XPG (X/Open Portability Guide)
58. XPM
59. XPointer (XML POINTER Language)
60. XRI (Extensible Resource Identifier)
61. XSD (XML Schema Definition)
62. XSDL (XML Schema Description Language)
63. XSL (Extensible Style Language)
64. XSL-FO (XSL Formatting Objects)
65. XSLT (Extensible Style Language Transformation)
66. XSS (Cross-Site Scripting)
67. XSSI (eXtended Server-Side Include)
68. XT
69. XT bus architecture
70. XUL (EXtensible User Interface Language)
71. XviD