| XCHS |
Extended Cylinders, Heads, Sectors |
| XCMD |
External Command |
| XCMD |
Extended Mode Command (Apple) |
| XD |
Execute Disable |
| XDCS |
X/Open Distributed Computing Services |
| XDF |
Extended Density Format (IBM) |
| XDLE |
Transparent Data Link Escape |
| XDMCP |
X11 Display Manager Control Protocol |
| XDP |
XML Data Package |
| XDR |
External/Extended Data Representation |
| XDS |
X/Open Directory Service |
| XETB |
Transparent End of Transmission Block |
| XETX |
Transparent End of Text |
| XEWA |
XML-Enabled Wide Area Search in Bioinformatics |
| XFA |
XML Forms Architecture |
| XFA |
Extended File Attribute |
| XFCN |
External Function |
| XFDF |
XML Forms Data Format |
| XFDL |
Extensible Forms Description Language |
| XFN |
X/Open Federated Naming Service |
| XFS |
X11 Extended File System |
| XG |
Extended General MIDI |
| XGA |
Extended Graphics Array (IBM) |
| XHTML |
Extensible Hypertext Markup Language |
| XID |
Exchange Identifier/Identification |
| XIE |
X11 Image/Imaging Extension (Standard) |
| XIE-DIS |
XIE Document Imaging Subset |
| XIM |
X11 Input Method |
| XIO |
Extended Input Output |
| XITB |
Transparent Intermediate Block |
| XKB |
X11 Keyboard Extension |
| XLATE |
Translate |
| XLFD |
X11 Logical Font Description/Descriptor |
| XLINK |
Extended Local Informatik Netz Karlsruhe |
| XLL |
XLink and XPointer Languages |
| XLL |
Extensible Linking Language |
| XLM |
Excel Macro Language (Microsoft) |
| XMI |
XTendbus Multibus Interface |
| XML |
Extensible Markup Language |
| XMM |
Extended Memory Manager |
| XMP |
X/Open Management Protocol |
| XMPP |
Extensible Messaging and Presence Protocol |
| XMS |
Extended Memory Specification |
| XMSN |
Transmission |
| XMT |
Transmit |
| XMTR |
Transmitter |
| XNS |
Xerox Network Services/Standard/System |
| XOFF |
Exchange/Transmitter Off |
| XOM |
X/Open Management |
| XON |
Exchange/Transmitter On |