X-ray

High frequency electromagnetic ray of short wave-length, capable of penetrating most solid substances.

X.25

International standard of the CCITT for packet switching.

X.400

A CCITT recommendation designed to facilitate international message and information exchange between subscribers of computer based store-and-forward services and office information systems in association with public and private data networks.

X.500

The CCITT now ITU recommendations (ISO9594) for the structure of directories for the maintenance of addresses used in electronic mail.

XML

Extensible mark-up language is an official recommendation by the World Wide Web Consortium as a successor of HTML (Hyper Text Mark-up language) it can be used to convey documents layout and contents from one computer application to another. XML is a subset of SGML.

XML/EDI

The exchange of structured information over the Internet using XML as the syntax.