Web, domains and email
XML
Abbreviation for Extensible Markup Language
In short and in plain language
XML is a text format. It describes data in an ordered way so that machines can read it.
Systems often use it to swap data. Examples are electronic invoices and interfaces.
Lists for search engines use it too. They show which pages a website has.
Definition
XML is a text format for describing structured data in a machine-readable way. Electronic invoices, interfaces and sitemaps for search engines often use it to exchange data between systems.