XML stands for eXtensible Markup Language XML is a markup language much like HTML. XML tags are not predefined in XML. You must define your own tags. XML is not a replacement for HTML. XML and HTML were designed with different goals: XML was designed to describe data and to focus on what data is. HTML was designed to display data and to focus on how data looks. HTML is about displaying information, XML is about describing information. This category will contain resource for you to learn and use XML.