What is RSS?

RSS stands for "Really Simple Syndication".
RSS enables you to distribute a list of headlines, notices, and sometimes content to a wide number of people. It is used by computer programs which then organize the headlines and notices for easy reading.

What is XML?

XML stands for "Extensible Markup Language".
XML is a language very similar to html and was designed to carry data. XML allows you to define your own custom tags in which to store your data. An XML file can then be shared across different information systems such as the Internet.

What is the difference between RSS and XML?

RSS documents are "written" in XML.