eXtensible Markup Language
A standard that forms the basis for most modern markup languages. XML is an extremely flexible format that only defines "ground rules" for other languages that define a format for structured data designed to be interpreted by software on devices. XML by itself is not a data format.
Examples of XML-based standards include xHTML, for creating web pages, RSS, for feeds of new information (such as news headlines), and SyncML, for managing personal data such as contacts, email, files, and events.